历史

西汉历史

楚汉之争

前209年，秦末，由于政令愈发严苛，而最终爆发陈胜、吴广「揭竿起义」的事件，先秦六国旧贵族也藉此时机纷纷复国。秦二世三年十月，楚分兵，拜宋义为上将军，项羽为次将，范增为末将，率军救赵；同时令沛公刘邦将砀郡兵西向攻秦。沛公先率楚军北上收陈胜、项梁散卒，至东郡，与王离军相遇。楚军出击秦军，于杠里大破东郡尉与王离所率领的秦军。宋义率楚军行至安阳按兵不动， 前207年四月，楚国贵族后代项羽率领诸侯联军在钜鹿之战消灭王离、降章邯秦军，同时刘邦北上先后开封之战 白马之战 颖川之战 洛阳之战 武关之战 蛲关、蓝田之战等战役后灭秦进军咸阳，而刘邦则入关推翻秦廷。。其后，项羽尊楚怀王为「义帝」，并自行分封天下（见《项羽十八诸侯列表》），封自己为「西楚霸王」，封刘邦为汉王。之后两股势力开始长达四年的楚汉战争。刘邦在萧何、韩信、曹参、灌婴、靳歙、周勃、郦食其、张良等人的协助下，最终在垓下之战中击败项羽，于前202年在定陶登基正式称帝，立国号「汉」，史称西汉。

西汉开国

汉高祖刘邦登基后，采用叔孙通的建议，恢复礼法，设三公和九卿，任用萧何为丞相，采取与民休息、清静无为的黄老治术政策，鼓励生产，轻徭薄赋。在政治上，则先分封异姓王、臧荼、彭越、英布等为王，以及一些功臣为列侯（详见《西汉开国功臣封爵列表》）。

称帝之后，异姓诸侯王势大，因此汉初几年对异姓王一一分别翦除，改封刘氏宗亲为王，仅存长沙王吴臣。后刘邦与功臣刑白马立盟誓：「非刘氏而王者，天下共击之」，史称「白马之誓」。汉初政府官员基本上由大大小小的功臣充任，从而形成汉初「布衣卿相」的政治格局。

此时，由于秦末以来动乱多年，国力虚弱，汉高祖在平定异姓王韩王信的叛乱时虽三次野战打败冒顿。匈奴越过句注山逃跑，采取诱敌之计包围刘邦，刘邦看出了端倪，派人前往打探情况，娄敬认为不可攻击，但数万汉军已越过句注山追击，刘邦不想打击汉军高涨的士气，部署追击，为了防止不测，派周勃南下攻打楼烦的三座城池，再跟主力会合，以备后援，后来刘邦被冒顿包围在平城，刘邦坚守白登山，冒顿一时不能攻下，7日后周勃的军队赶到，攻打冒顿的包围圈，为刘邦解围，汉军打败匈奴，由于国力虚弱无法大规模反击匈奴。从此以后，汉朝采用和亲政策，以婚姻和财宝换取和平。据史料记载，前后一共送去10位宗室之女，即冒顿单于于前200年、前192年、前176年所收到的3位公主，老上单于于前174年、前162年所收到的2位公主，军臣单于于前160年、前156年、前155年、前152年、前140年所收到的5位公主。

吕后专政

公元前196年，吕雉利用计谋于长乐宫钟室将淮阴侯韩信杀死，灭三族。汉高祖去世后，太子刘盈继位，是为汉惠帝。惠帝时年16岁，大权尽为太后吕雉（吕后）掌握。因汉高祖刘邦在世时，刘邦之宠姬戚夫人曾想谋立己子赵王如意为太子，结果遭到吕后和功臣们的强烈抵制而未能成功。刘邦去世后，吕后即毒死赵王刘如意。刘如意死后，吕后使人挖去戚夫人的双眼、熏聋其耳、灌药致哑、断其手足，然后丢进茅房里，命名为「人彘」，意即「如猪之人」。对其他刘氏诸王也多加残害。又逼汉惠帝立自己年仅十岁的外甥女张嫣为后，史称「孝惠张皇后」。但张氏实在年纪太小，一直无法怀孕。吕后于便设计张氏假装怀孕，然后强取惠帝宫女所生之子，即前少帝，并伪称为张皇后所生，又秘密处决了那个宫女，于是前少帝被立为皇太子。惠帝因吕后的残暴而惊恐，数年后抑郁病逝。前少帝逐渐成长，获悉他的生母已为吕后所杀，公然表示长大后将会报复吕后。吕太后盛怒之下，便将他监禁于永巷中，并对外宣称前少帝生病，大臣均不得见。后来更废了前少帝，并暗中诛杀。五月，立恒山王刘山为皇帝改名刘弘，即后少帝。吕后临朝称制，开汉代皇太后临朝称制之先河，且数为后世所效仿。

吕后称制，大封诸吕，并欲王诸吕，遭到时为右丞相的安国侯王陵坚决抵制。吕后伪升王陵为太傅，实欲夺其大权，然后大封吕氏外戚为诸侯王和列侯。吕后为了增加吕氏的筹码，将吕氏之女与刘氏宗室联姻，不仅拥有权力，也可以藉此监视刘氏子孙的一举一动。并且吕氏外戚亦掌控禁军，刘氏皇权遭到严重威胁。而朝中大臣多为随汉高祖的开国功臣，他们表面上不敢反对吕后，但却已经开始为此准备。吕后临终时任命吕产为相国，先封吕禄为赵王，再任命他为上将军，独掌军权。而以陈平、周勃为首之功臣派亦做好准备，并与刘氏皇族联合。吕后一死，功臣派与皇族立即先发制人，发动政变，一举诛平吕氏外戚，废掉少帝刘弘，迎立汉高祖刘邦与薄氏之子代王刘恒为帝，是为汉文帝。

吕后掌权时代，惠帝七年，临朝称制八年，前后共15年。高层之权的夺权并没有影响到国家的大政方针。吕后仍能忠实执行刘邦生前所定的休养生息、恢复民力的政策。相国（或丞相）之人选一如刘邦生前安排。萧何去世后，曹参继任，举事无所更改，一遵萧何约，力行清静无为之政，史称萧规曹随。除此之外，吕后秉政，继续宽刑薄罚，如废除「三族罪」、「挟书律」等秦朝恶法。对外政策上亦能理性冷静处理，继续「和亲」政策，避免战争。这样，吕后时期，国家经济呈上升之势，国力亦有很大增强。史称：「孝惠皇帝、高祖之时，黎民得离战国之苦，君臣俱欲休息乎无为，故惠帝拱己，高后女主称制，政不出户，天下晏然。刑罚罕用，罪人是稀。民务稼穑，衣食滋殖。」

文景之治

汉文帝之皇后窦太后非常喜欢《道德经》，尊崇道家，因此汉景帝与窦氏宗族都必须学习道家学说。汉文帝和儿子汉景帝在位期间，继续秉持黄老无为的治国理念，奉行「无为无不为」的方针，实行轻徭薄赋、力行节俭的与民休息政策，恩威并施，以弥补秦末民变和楚汉战争的多年动乱带来的巨大破坏，使人民负担大大得到减轻，社会生产得以迅速恢复。通常认为文景之治的主要作为是汉文帝与汉景帝。实际上，窦太后在文景之治时代所起的作用也是举足轻重的。《史记》卷三十《平准书》对文景之治作出仔细的描述，当中提到两帝在位其间，并无重大事故，百姓人给家足。国库累积上亿的铜钱，因为久而不用，串钱的绳子都烂了。粮仓里堆满谷子，由于太多放不下而只能放在仓外，以致腐烂而不能食用。

文帝在位时，存在诸侯王国势力过大及匈奴入侵中原等问题。文帝对待这些问题采取的是异常谨慎而且又有效的手法。对待诸侯王，文帝采取以德服人的态度，小错不纠，在中央弱势的时候成功的安抚住各地蠢蠢欲动的诸侯，为后来景帝处理七国之乱造就一批忠心耿耿的诸侯王和大臣。最重要的两个大动作是：安抚吴王，使得吴王在最年富力强的时候没有假借丧子之仇反叛；在齐王死后将齐国一分为七，既满足齐王的儿子们称王的需求，为自己赢得贤德之名，又消除最大的一个诸侯国齐国。假如文帝的谨慎稳重的做法被一直持续下去，汉朝也就不会发生后来的七国之乱，诸侯王问题亦有希望能够和平解决。文帝二年（前178年）和十二年（前168年）分别两次「除田租税之半」，即是租率最终减为三十税一（3.33%）。文帝十三年，还把土地税完全免了。同时，对周边敌对国家也不轻易出兵，维持和平，以免耗损国力。这就是轻徭薄赋的政策。文帝生活也十分节俭，宫室内车骑衣服没有增添，衣不曳地，帷帐不施文绣，更下诏禁止郡国贡献奇珍异物。因此，国家的开支有所节制，贵族官僚不敢奢侈无度，从而减轻人民的负担。这就是休养生息的政策。文帝时，缇萦上文帝，痛陈肉刑的弊端，并愿意代父赎罪，亦即后人熟悉的故事「缇萦救父」。文帝纳言废除肉刑，下诏废除黥刑、劓刑、刖刑等刑罚，改用笞刑代替，并饶恕其父，可见文帝是宽容的一代贤君。

景帝即位不久，就采纳晁错的建议，削夺诸藩王的封地，引发各王的担忧，而在景帝三年正月（zh-hans:公元; zh-hant:西元;前154年）爆发以「清君侧」为名义的「七国之乱」，汉景帝因此腰斩了晁错，以寄达到平息叛乱的目的。但是七国之乱并未因此缓和，景帝任用周亚夫出兵平叛，在三月即告弭平，各诸侯国的势力因此极大削弱。七国之乱以后，景帝开始专心打理朝政，据说景帝十分朴素，仁厚爱民。除了平定七国之乱以外，从来没有大规模用过兵，和匈奴的战争始终控制在一定的规模内，依然对匈奴采取和亲政策。

在与匈奴和南越国（南粤）保持和平的同时，也在积蓄国力，透过马复令等措施来积极备战；此一时期史称「文景之治」，是中国成为大一统帝国时代以来，第一次被传统历史学家赞誉的时期。

汉武盛世

景帝驾崩后，其子刘彻即位，是为汉武帝。武帝在位共五十四年，是清朝康熙皇帝以前以及汉朝在位最久的皇帝，也就是中国历史上在位第三长的皇帝。在位期间（在位前141年—前87年）承上启下，开创了汉武盛世，并采取一系列改革措施，锐意进取，使得西汉的政治、经济及军事大展新风貌，开创中国前所未见的波澜盛世。可惜他好大喜功，在其政治生涯中留下了一大污点。

在政治上，武帝加强皇权，建立年号「建元」，始开中国以皇帝年号纪年的先例，采纳主父偃的建议，施行推恩令，削弱诸侯藩王的势力，从此，诸侯藩王的势力不再能够对中央朝廷构成威胁；后又以诸侯献上的黄金成色不纯为由，取消百馀位列侯的爵位，即史书上所称的「酎金失侯」事件。经此二次事件后，中央集权得到大大的加强。文化上，废除过去以「黄老学说、无为而治」的治国思想，积极治国；并采纳董仲舒「罢黜百家，独尊儒术」的建议，使儒家思想从此逐步成为中国历经二千年的「主流思想」。

对外关系上，积极对付西汉的最大外患—匈奴。在此期间，先后出现卫青、霍去病、李广、李陵、李广利、公孙贺、公孙敖等杰出名将，经过武帝、昭帝、宣帝三朝数十年用兵后，终于彻底击溃匈奴单于，使其「漠南无王庭」；又吞灭南越国，征讨朝鲜，使汉朝成为当时的东方霸主。外交上，两次派张骞出使西域，开辟丝绸之路，并先后以两位公主刘细君、刘解忧和亲西域大国乌孙，而达到离间西域和匈奴关系，进而联络西域的目的。

汉武帝晚年笃信巫术，听信江充谗言，导致发生著名的「巫蛊之祸」，在这件事中，公孙敖、公孙贺、公孙敬声、卫君孺（卫子夫之姐）、卫伉(卫青长子)、卫伐（卫青次子）、及太子刘据因而死亡。而皇后卫子夫也因过度伤心而自杀。

西汉经过多年对外战争，文景之治的积蓄耗费殆尽，经济遭受巨大冲击，国力也出现衰退的局面。为此，在巫蛊之祸后，汉武帝利用远征军失利的时机发表著名的「轮台之诏」。辛德勇认为，轮台诏不是罪己诏，关于汉武帝罪己是资治通鉴的虚构，汉武帝死后并未改变西汉对外战争的基本国策。而田馀庆认为汉武帝晚期改弦易辙。为提振经济，汉武帝将铸币、盐铁收归中央管理，加强农业生产，实行和籴法，开凿白渠，并创立均输、平准政策，统购统销，干预物价，加强国家在经济中扮演的角色。

昭宣中兴

武帝去世后，钩弋夫人（赵婕妤）之子，年仅八岁的刘弗陵即位，是为汉昭帝。汉昭帝登基之初，由上官桀、金日磾和霍光三人共同辅政。但是在元凤元年（前80年），爆发元凤政变，上官桀被杀，霍光从此大权独揽。霍光延续武帝在位晚年的政策，对内休养生息，放宽盐铁专卖制度，提高儒生地位。昭帝死后，武帝孙昌邑王刘贺即位。他行为放纵（在位27天做出1127件荒唐的事，不排入帝序），密谋排除霍光，但反被霍光所废。之后霍光又迎立刘病已(后改为刘询)即位，是为汉宣帝。本始元年（前73年），霍光还政于宣帝。地节二年（前68年），霍光去世。此后宣帝将霍氏集团一网打尽。但是，宣帝继续奉行霍光的治国路线，大力整顿吏治，劝民农桑，抑制兼并，降低国家在经济中的角色。这段时期，汉朝不仅内政清明，而且对于匈奴继续保持强势，在汉宣帝神爵二年（前60年）设立西域都护以加强对西域三十六国所处地区的联络与控制。经过昭宣二帝的休养生息，国家经济得以从武帝中期以来的衰颓困境下明显恢复，并使汉帝国达到空前臻美的状态，史称「昭宣中兴」。

王莽夺位

宣帝死后，汉元帝刘奭即位，西汉开始走向衰落。元帝「柔仁好儒」，对于社会秩序采取放纵态度，经常下令大赦，并且放弃了汉初以来迁徙关东豪强充实关中陵寝地区的制度，导致盗贼遍地，土地兼并日益严重，也致使皇权旁落，外戚与宦官势力兴起。他死后，成帝刘骜即位。汉成帝时汉成帝的舅舅、王凤与许平君的堂弟、孝成许皇后的父亲许嘉并立为大司马车骑将军。后来小许皇后失宠、赵飞燕赵合德姐妹崛起，汉成帝没有男性后代，外戚王凤、王莽（田齐后人）逐渐控制了政权，王氏兄弟四人和侄王莽相继为大司马大将军。成帝死后，由定陶王之子哀帝刘欣即位，哀帝有「断袖之癖」，终日与他宠信的董贤厮混相好，外戚王氏的权力一度受压抑。此时国家已是一片末世之象，民间「再受命」说法四起。元寿二年（前1年）八月，哀帝去世。太皇太后王政君派王莽接替董贤成为大司马，并迎接中山王刘衎即位，是为汉平帝，改元元始。但是，刘衎已沦为王莽的傀儡。五年后，王莽毒死仅14岁的平帝，并立刘婴为太子，号「孺子」，自己担任「假皇帝」，初始元年十二月朔（9年1月15日），王莽正式称帝，以刘婴为定安公，建立新朝。

东汉历史

光武中兴

新莽天凤五年（17年）绿林起义爆发，23年，仅十五年的新莽政权在赤眉、绿林民变下灭亡。同年2月，绿林军拥立汉宗室刘玄作皇帝，恢复汉的国号，年号更始。25年赤眉军向城阳景王刘章占卜，立景王后人刘盆子为帝，随后击败绿林军，更始帝刘玄向赤眉军投降。通常刘玄被认为是西汉最后一位皇帝，但也有认为是孺子婴才是西汉最后一位皇帝，原因是他被王莽篡位。若把一代而亡的新朝计入汉代历史，那刘玄可算是西汉最后一位皇帝，因为刘秀建立的是新的刘氏宗室政权。

汉更始三年（25年）六月，原本服从更始帝的汉朝宗室刘秀在鄗县（今河北高邑东南）之南即皇帝位，是为光武帝，灭刘盆子，仍沿用汉的国号，以这一年为建武元年，定都雒阳，史称东汉。即位后，于37年终于消灭赤眉、隗嚣、公孙述等割据势力，统一全国。

汉光武帝废除王莽时的弊政，建武二年（26年），光武帝下令整顿吏治，设尚书六人分掌国家大事，进一步削弱三公（太尉、司徒、司空）的权力，加强中央集权；同时清查土地、新定税制、振兴农业，使人民生活逐步稳定下来；另外提倡儒术，建立太学，设置五经博士，与尊儒并行的便是表彰气节，因此士大夫争相以名节为目标，为淳美的政教，奠下基础；对匈奴等外部势力实行防御的策略，对外戚严加限制，史称光武中兴。但由于分封土地，也造成土地兼并情况日益严重，地方豪强势力兴起，为东汉的最终灭亡埋下隐患。

明章之治

汉明帝和汉章帝在位期间，东汉进入全盛时期，史称「明章之治」，此时推行的是儒家，与西汉的「文景之治」同为各时期的鼎盛。期间，窦固以班超出使西域，班超在西域长驻三四十年，不仅善于使用武力威慑各国，更善于运用外交手段去联络距离较远的国家。但匈奴人亦同样在开展类似的行动，推翻各国亲汉的政权，再与新政权结盟。双方不断地反覆攻防，一直到20年后，班超之子班勇才完全掌控西域。章和二年（88年）十月，车骑将军窦宪领军出塞，击破北匈奴，登燕然山，令班固作铭命，史称燕然勒石。二年后，永元三年（91年）窦宪派兵再次出击，出塞五千里进攻金微山，大破北匈奴单于主力，斩名王以下五千馀人，俘虏北单于皇太后，北单于仓皇逃窜不知所终，从此扫除数百年来匈奴对汉朝北方边境的威胁，汉朝国势也再一次到达汉武帝时期的鼎盛；佛教也在此时传入中国。但是在章帝后期，外戚窦氏日益跋扈，揭开东汉后期外戚与宦官两股势力争斗的序曲。

戚宦争权

88年，年仅卅一岁的汉章帝突然驾崩，时仅十岁的太子刘肇即位，是为汉和帝，他即位伊始，实际上朝政都由窦皇后操纵，国家政治日益腐败。窦氏的跋扈引发和帝的不满，不久年仅14岁的和帝就抓捕外戚窦宪，外戚势力开始衰弱，和帝信用宦官，从此东汉的政治沦为外戚和宦官两股势力的争斗。不过，和帝仍然在政事上非常勤奋，不失为英明之主。元兴元年冬十二月，年仅廿七岁的和帝病逝。出生仅百日的少子刘隆即位，是为殇帝。殇帝仅在位8个月就驾崩。接替即位的是清河王刘庆之子安帝刘祜。他即位早期由太后邓绥临朝理政。邓太后勤俭节约，任用贤良，同时对自己家族的势力有所限制，却也对宦官势力纵容。建光元年（121年），邓太后逝世，安帝亲政，将邓氏家族诛杀殆尽。安帝依赖外戚宋氏和阎氏以及宦官的力量。听信奸臣，肆意无忌，朝政昏庸不堪，东汉快速衰落。延光四年三月，汉安帝在南巡途中死在叶城。外戚阎氏秘不发丧，拥立汉章帝之孙济北王刘寿之子刘懿，史称汉少帝，其在位仅200馀日就病死。少帝死后，阎氏家族密谋再立傀儡，被中常侍孙程击破，阎氏家族被诛杀。孙程迎立济阴王刘保，是为汉顺帝。在顺帝执政早期，宦官势力膨胀，却引发社会各界的反弹。阳嘉元年（132年），贵人梁妠立为皇后，从此梁氏外戚势力开始崛起，梁妠的兄弟梁冀被任命为大将军。汉安二年（143年）八月，顺帝病死，太子刘炳即位，是为冲帝，即位时年仅2岁，由梁太后临朝执政。永嘉元年（145年）正月初六，刘炳驾崩，年仅三岁。正月廿五日，梁冀拥立刘缵即位，是为质帝。质帝非常聪颖，称梁冀为「跋扈将军」，结果不久质帝就被毒杀。

本初元年闰六月初七日，大将军梁冀拥立汉章帝之孙刘志即位，是为汉桓帝。桓帝年少，因此继续由梁太后临朝执政。桓帝即位之初，朝政由梁冀把持。桓帝对他暗中也颇为不满，延熹二年八月初十，桓帝派兵士包围梁宅，梁冀与妻子双双自杀，梁氏外戚势力土崩瓦解。宦官成为新的权力中心。单超、徐璜、具瑗、左悺、唐衡五人被封为县侯；单超食邑两万户，后又封为车骑将军，其他四人各一万户，世称五侯。五侯贪婪放纵，终致在延熹九年（166年）引发第一次党锢之祸。永康元年十二月廿八日（168年），汉桓帝驾崩。桓帝没有留下子嗣，由河间王刘开的曾孙刘宏继位，是为汉灵帝。灵帝即位之初，就引发以窦太后、窦武为首的外戚势力和以曹节、王甫为首的宦官势力的激烈权力斗争。宦官成功发动政变，杀死窦武。外戚势力被削弱。宦官随后制造第二次党锢之祸。而灵帝本人骄奢淫逸，为填补财政公开卖官，朝政腐败。

大乱国崩

数十年的政争，长时间的羌乱以及天灾动摇汉朝的民生，终于在184年爆发由太平道教主张角引发的黄巾之乱，黄巾军以「苍天已死，黄天当立；岁在甲子，天下大吉」号召数十万民众参与，虽然叛乱不久即告平定，但是东汉朝廷经此一役已实力大减,之后相继爆发北宫伯玉之乱和张举、张纯叛乱。中央朝廷为了尽快平叛，又将军政权力下放给各州的州牧。刘昭认为设立州牧是导致天下大乱的原因。

汉灵帝死后，外戚大将军何进和宦官双双火并同时死亡，终于结束戚宦之争。但董卓掌权后，废少帝刘辩为弘农王，改立陈留王刘协。此举引发关东州郡背叛中央，最终演变成东汉末年军阀割据一方、群雄逐鹿的局面。董卓为了躲避关东联军，焚毁首都雒阳并迁都长安。董卓被吕布诛杀后，经过几年混战，出现把持朝廷的曹操、位于河北的袁绍、位于淮南的袁术、位于江东的孙策、位于荆州的刘表、位于益州的刘焉等势力。其中曹操「挟天子以令诸侯」，架空汉室权力，消灭各路割据势力，并在官渡之战中消灭最强大的敌人袁绍军队的主力，基本统一北方。

汉献帝建安十三年(208年），罢三公官，复置丞相，曹操任丞相，独揽大权。曹操挥军南征，却在赤壁之战中被孙权、刘备联军击败，曹操被迫回北方，巩固中原。不久刘备以荆州为根本，进占益州，曹刘孙三分天下之势开始形成。而在这段期间，汉献帝只是一个傀儡皇帝，真正实权掌握在曹操手中。曹操先是晋位为魏公，不久又晋位魏王。建安二十一年（216年），汉献帝不再颁下诏书，汉皇帝向臣下发布诏书的权力被剥夺。汉至此已名存实亡。

建安25年（220年）春正月庚子，曹操去世，其世子曹丕继任汉丞相，袭封魏王。同年汉魏禅代。221年，刘备称帝。江东孙权虽向魏称臣，内政外交皆自主，几年后孙权亦称帝，国号吴，三国时代正式开始。曹丕代汉后，汉朝宗室遭到曹魏禁锢。这一措施直到西晋泰始二年（266年）才被废除。

季汉历史

建安25年（220年）十一月，曹丕迫汉献帝「禅让」帝位，东汉结束。而曹丕代汉建立魏后，割据益州的汉朝宗室刘备随即称帝，宣布继承汉朝法统，史称蜀汉。诸葛亮主政期间，继承刘备遗志发动五次北伐，期望攻占陇西、克复中原，然而均遭到魏军阻挡而未能有进一步的进展。直至公元263年，曹魏攻入蜀地，汉后主刘禅投降，蜀汉亡，历二帝统治，共42年。

疆域

汉初，因秦末民变和楚汉战争致使国力虚弱，只得退让防守。河南地区在秦末民变爆发时为匈奴占领。期间南越（南粤国），闽越（闽越国），黔中地区亦先后独立。国土大幅减缩。

文景之治后，汉武帝时期，武功鼎盛，国土大幅扩展。元朔二年（前127年），卫青北击匈奴，收复河南地、陇西、北地、上郡的北部，置朔方、五原二郡。云中、雁门二郡的北界也向外扩展。西汉的北部疆界至此推到河套，阴山以北。元狩二年（前121年），汉将霍去病出陇西击灭居于河西走廊的匈奴部落，以其地设酒泉郡。后又分割为张掖、敦煌、武威三郡。连同在湟水流域设置的金城郡，合为五郡，开始对西域的控制。建元三年（前138年），东瓯迫于闽越王的威胁，举国内迁到今江淮流域。元封元年（前110年），汉军又平定闽越国，其地划入会稽郡。元鼎六年（前111年），汉军平南越国，又占有海南岛，在该地设十郡。在西南方向，汉军征服诸国，边界推移到云南哀牢山和高黎贡山。元封二年-元封三年（前109年—前108年），汉军在东北地区平定卫氏朝鲜，设置辽东四郡。边疆形势蔚为改观。

新莽末年，疆域萎缩。东北撤销真番、临屯二郡。西南地区由七郡变成五郡，并且放弃海南岛上的珠崖、儋耳二郡。光武中兴后形势得到改观，版图基本恢复。东汉末期，中原战乱不断。曹操放弃定襄、云中、五原、朔方、上郡、北地六郡。河套、陕北、晋西北、河北北部地方先后放弃。高句丽与林邑两国蚕食东北及南方国土。只有西南地区扩展至大盈江一带，其中益州郡、牂牁郡、永昌郡，与西南滇王（前278年—115年）、夜郎王（直至前27年）、哀牢王（直至76年）及钩町王共同并存。

在汉朝最大「领土」范围内：东北的鲜卑、北边的匈奴（汉朝打败了匈奴）、中亚（汉攻大宛之战、郅支围城战）、贵霜（汉朝打败了贵霜）、青海西藏的羌人都是附属国。汉朝打败了匈奴后，汉朝在现代西伯利亚以及北极圈地区修建了阿巴坎遗址、燕然勒石等建筑。

西域在汉朝早期是指南疆一带，后来扩展到天山以北和中亚东部。西汉中早期，西域地区为匈奴所控制， 随后武帝征服西域，西域成为汉朝的领土。

汉武帝时期，于建元三年（前138年）派张骞出使大月氏以联合夹击匈奴。张骞在路上一度被匈奴扣押，并在匈奴娶妻，十馀年后逃出，经大宛等国到大月氏，但未能取得夹击匈奴的答复。后来张骞东返，又被匈奴扣押。直到元朔三年（前120年）才返回长安，回来时只剩他和随从堂邑父两人，他的匈奴妻子也一并来到长安。

元狩四年（前119年），汉武帝第二次派张骞出使西域，约乌孙共击匈奴。虽然张骞未能说服乌孙国王夹击匈奴，但是张骞却与其使节先后游历大宛等国，后来亦由各国使节陪同，返回长安，从此以后，汉朝与匈奴反复在西域地区争夺。元封六年（前105年），汉武帝以细君公主与乌孙和亲。细君死后，汉又在太初四年（前101年）以解忧公主续嫁。同年，汉朝大破大宛，西域南道各国都转投汉朝。汉武帝在乌垒设使者校尉，又在渠犁屯田。

到宣帝神爵二年（前60年），汉又驱逐匈奴驻在西域的僮仆都尉，控制西域北道，设立西域都护，总管西域事务，还在乌孙国都赤谷一带屯田。元帝时，又增戊己校尉，在车师前王庭屯田。西汉末年，西域分为五十五国。

王莽时期，贬去其王号，降为侯，西域与汉关系趋紧，匈奴势力再入。

东汉明帝初年以后，汉朝又恢复同西域的联系，并于永平十六年派将军窦固入伊吾庐屯田驻兵，次年在乌垒设西域都护，派班超负责西域事务。永元九年（97年），班超派甘英出使大秦(罗马帝国)。甘英经条支、安息等国，到大秦西界望海而还。

随著西域局势的逐步趋于稳定，商旅往来日益频繁，丝绸之路在西汉后期形成。这也是世界历史上最重要的商道之一。汉朝遣使者至安息、奄蔡、条支和身毒等国，一年多则十馀批，少则五六批，携带金币帛等物品，需要至少两三年，甚至八九年才能返回长安。中国运往西方的物产以丝绸、铁器和漆器为主；而良马、骆驼、香料、葡萄、石榴、苜蓿、胡麻、黄瓜、胡豆和胡桃等也源源不断进入中国。

季汉主要占领益州，共分为二十二郡，拥有一百三十一个县国，刘备于建安十三年（208年）赤壁之战后始得荆州的南郡部分及长沙、武陵等荆南4郡。建安十九年（214年）入蜀取得益州，明年与孙权议定平分荆州，219年刘备于汉中之战打败曹操得汉中郡。至建安二十四年（219年）时，计此时共辖有2州21郡1属国。同年孙吴击取荆州而丧失南郡、武陵郡、零陵郡3郡，诸葛亮北伐曹魏取得武都郡、阴平郡2郡，分割设置数郡。季汉灭亡以前，计辖有1州22郡。

政治体制

西汉前期的中央行政制度早期仿效秦朝实行三公九卿制，丞相、太尉、御史大夫称三公，丞相管行政，是文官首长；太尉管军事，是武官首长；御史大夫为副相掌监察，辅助丞相掌管政治事物。而在西汉，还有一条不成文的规定，即必须做御史大夫后才能做丞相。而在御史大夫之下，还设有御史中丞，掌管宫内事务。九卿则是太常（掌祭祀鬼神，兼掌教育事宜）、光禄勋（掌宫殿门房及皇帝侍卫随从，兼掌州郡所荐三署郎人选之考选铨叙等人事事务）、卫尉（掌宫城卫兵）、太仆（掌车马，兼掌全国牧政及驿站）、廷尉（掌法律审判）、大鸿胪（掌礼宾，兼掌外国及属国交往）、宗正（掌宗室族谱及诸侯王公主等督训）、大司农（掌全国经济及财政用度）、少府（掌皇室财政，兼掌官营手工业作坊）。另外又有将作大匠（掌国家工程营缮）、执金吾（掌京师治安）、大长秋（协助皇后管理后宫），与九卿并称「十二卿」。

汉武帝时期，皇权开始大幅膨胀，为压制位高权重的丞相，内廷尚书令的地位大幅抬升。汉武帝将身边重臣如严安、主父偃、朱买臣等为郎加以侍中，与尚书令共议军国大事，组成中朝。原以宰相为首的三公九卿组成外朝。

绥和元年，汉成帝时改御史大夫为大司空，元寿二年，汉哀帝把丞相改称大司徒，东汉时改称司徒，负责掌理教化，东汉光武帝时，三公权力再次大幅被削弱，尚书台权力得到提升。东汉早期的三公是司徒、司空和太尉，三公职位虽高，但其权力不复西汉之巨，仅馀每年考核天下州郡人民、土木、兵马之政及分督九卿的督察权，政事综理之责内移至禁中尚书台。尚书台掌管全国政事，直接对皇帝负责。尚书台设尚书令一人，为其主管长官；尚书仆射一人，为尚书令之副；左右丞各一人，为令、仆之佐。尚书令原分四曹，后增至六曹，每曹有尚书一人，侍郎六人。同时，东汉政府还设立三套监察机构，分别是中央的御史台、兼具京官和地方官身份的司隶校尉与地方的州刺史。光武帝同时设立中常侍等宦官职务。一系列的措施大力削弱的三公的权力，尚书则权高位低，同时也为之后的宦官乱政埋下隐忧。

汉献帝建安十三年，曹操掌控下的朝政下令废除三公制，恢复汉初旧制，复设丞相，由曹操出任，军国大事一由丞相统任。

行政区划

西汉初，刘邦封异姓王七人。但由于对功臣的猜忌，不久又相继削除，同时大封同姓诸侯，这些王国「大者或五六郡，连城数十，置百官宫观，谮于天子」。地方王国势力的强大导致中央政府所实际控制的区域萎缩。吕后时期，增加外戚诸侯王。到文帝时期又纷纷铲除，增加刘氏诸侯王。但是地方王国势力的膨胀已经对中央政府构成严重威胁。文帝接受贾谊的建议，用分地的方法削弱诸侯的势力。景帝即位后采纳晁错的建议，直接缩减王国的封地，引发诸侯王的强烈反弹，导致吴楚七国之乱爆发，但未几就宣告失败。武帝后，采纳主父偃的建议，推行推恩令，规定诸侯王位由嫡子即位，而馀子皆分一县或一乡的土地。因此王国不断缩小，汉郡不断扩大，加上边郡的开扩，汉朝中央政府对地方的控制力日益加强。同时，政府将大量面积较大郡予以分割。到平帝元始二年，共有郡国103个，辖县、侯国、公主沐邑、道（少数民族聚居地）等县级政区1587个。

「州」作为行政区划，在西汉时期萌芽，到东汉宣告形成。武帝元封五年（前106年），始在郡之上又设十三行部，每部派一刺史，每个行部管辖若干郡（国）。但此时的行部是监察区，还不是真正意义上的行政区。东汉末年，地方多事。灵帝中平五年（189年），朝廷选重臣出任刺史，称州牧，掌一州军民。州从监察区变为行政区。至此，中国地方行政由原本的郡县两级制度变为州郡县三级制。

十三个州部为：司隶校尉部（治雒阳）、徐州刺史部（治剡县）、青州刺史部（治临淄）、豫州刺史部（治谯县）、冀州刺史部（治高邑）、并州刺史部（治晋阳）、幽州刺史部（治蓟县）、兖州刺史部（治昌邑）、凉州刺史部（治陇县）、益州刺史部（治雒县）、荆州刺史部（治汉寿）、扬州刺史部（治历阳）和交州刺史部（治龙编）。献帝兴平元年（194年），又分凉州置雍州刺史部。则至汉亡，全国有十四州。

教育

汉承秦制，于诸子百家各立博士，统属于太常，秩比六百石，其数多至数十人，数量多达数十人。但汉初朝廷所崇信的学术，黄老之外，便是申韩法家学说，对于儒家思想并不重视。到文帝时的贾谊，儒家思想才逐渐兴起。武帝建元五年（前136年），增置五经博士，形成儒家独大的局面。其后武帝又应公孙弘、董仲舒之请，于元朔五年（前124年）为五经博士置弟子员五十人，以受经术，期限为一年。弟子员的来源，主要选自民间十八岁以上的子弟，此外各郡具低级官吏品学兼优者，也可担任弟子。毕业后，能通一经以上的可补「文学掌故」，等第高的可充任郎官，但只限于白身受业者。地方官吏出身的，则多派充九卿、列卿或郡太守的属官。

宣帝时，五经博士增至十二人；王莽时，增设乐经，共为六经，每经设博士五人。弟子员也代有增加，昭帝时已满百人，宣帝末至二百人，元帝时千人，到成帝时多至三千人。从太学的大量扩充，显示西汉儒学教育的日益发展与儒家政治势力的日益膨胀。东汉光武帝也于建武五年设学于京师，置博士十四人。太学生更不断增加，质帝时，太学生已多至三万人。

察举制度

汉代察举制度可分为两类：一是诏举，当国家有特殊需要时，下诏命官吏推举人才。二是孝廉之举，是由郡国按时向中央保荐当地的人才。荐举为主，考试为辅，是两汉察举制的基本特点。

高祖曾于十一年（前196年），下诏徵求贤才，此举开汉代选举制的先河。其后文帝二年（前178年），曾下诏命「二三执政」举「贤良方正、能直言极誎者」。至十五年（前165年），再度诏举上项人才，保举者的范围则扩大到侯王、公卿和郡守，由皇帝亲自策问，汉的选举制自此开始普遍推行。其后武、昭、宣等朝，也曾屡次诏举人才，都以贤良为主。西汉的名臣鼂错、董仲舒、公孙弘等都以贤良入朝为官。汉代诏举，除贤良外，尚有「文学高第」、「茂材异等」、「孝悌敦厚」、「勇猛知兵法」、「明当之务、习先圣之术」、「明阴阳灾异」等名目，被举者大抵为现任官吏。东汉时，诏举由特举变为岁举，又称茂材之举。选举的标准有四：即德行高超，经明行修，明晓法律和刚毅多略。每年由光禄勋、御史、司隶校尉及各州剌史等实责推举。推行荐举、察举等方法的结果是门阀制度的大大发展，大量士族世家出现，与外戚、宦官形成东汉时期的三大势力，基本垄断国家政治。

汉朝的选举制度是察举制，以地方推荐为主，考试为辅，考试与推荐相辅而行。推荐过后是还要经过考试覆核；覆核合格后才能量才录用。无论是特举贤良方正，还是岁举孝廉、茂才，均须经过中央覆试。汉代察举制下的考试，在西汉时并不占主导地位，考试只是区分人才高下，授官大小的参考 ，这与后世以考试为主、以推荐为辅的科举制截然不同。至东汉时，为纠正察举荐人之滥，开始注重考试，形成察举与考试相结合的选士制度，而且考试成份日益增加。在推荐基础上加强考试，这是汉代察举制发展的新趋势。荐举为主，考试为辅，是两汉察举制的基本特点。

法律

汉朝的法律是律、令、科、比四种。律是有系统的成文法律，具有传统性；令，则是君主视需要随时颁布的法律，与律具有相同的效力；比，或称决事比及法比，是无成法可引用时用来比类决事的法律。汉律最早是萧何制定的《九章律》，后来加上叔孙通《傍章》十八篇，张汤《越宫律》二十七篇，还有赵禹《朝律》六篇。汉律到武帝时期便已完备，但也由于法条过多，产生判决不公的情况发生，亦难免有自相矛盾之处，给予官吏做坏事的机会，昭帝以后的几位皇帝，虽然有心改善，但始终没有彻底执行。

西汉中期以后，儒学开始兴盛，学者论法，多主张以德为主，以刑为辅。到了东汉时期，光武、明帝，虽然提倡儒术，仍然崇尚法制。章帝时，采纳陈宠的建议，除去严酷的法律五十几条。和帝后，外戚与宦臣，轮流把持朝政，他们一向违法乱纪，视法典于无物，法家的儒化，使东汉政治趋于迂缓，丧失西汉盛时发扬蹈厉的政治精神，儒家虽然兴盛，却对国事帮助不大，这种情况维持至东汉结束为止，献帝时，曹操当国，用法尚严，命应劭删定律令，作《汉仪》二百八十篇，虽然一度走向法治，但东汉不久被曹丕篡位而灭亡。

军事制度

徵兵制

汉朝早期实行徵兵制度，男子廿三岁起至五十六岁之间，服役两年。一年在地方服役，名为正卒；另一年戍守边郡，叫做戍卒。正卒在本郡服役，划分兵种，加以训练。屯戍各分为两种：在京城或王国都城屯戍的称「卫士」，在边郡屯戍的称「戍卒」。服役期满后，役男即可返乡，不过仍有随时应召服役的义务。兵役之外，还有繇役，即每年为郡县政府服力役一月，服役者称「更卒」，同样也是五十六岁免役。

京师的驻军分为两支，一支为南军，守卫宫城和官署，另一支为北军，屯驻于三辅地区保卫首都其他地区。它们名称的来源，是汉的长乐宫、未央宫等宫，都在长安城的南部，故宫廷卫军集中于城南，守城军队的重心则在城北，因此有南北军之称。所谓卫士，即是指南军士兵，由三辅以外的各郡役男轮番充任。但卫士是有经过选拔的，并非所有的役男都当卫士，不充卫士的则当戍卒。北军的士兵，则由三辅的役男轮流担任，可能即是服正卒役。至于王国的卫士，则只在本国首都服役，不须屯戍京师。屯边的戍卒，大都是关东人，此外尚有少数当地人；他们在边塞城堡中，担任守望的工作。

服正卒役的役男，由各县集中于郡，划分兵种，给予训练。当时的兵种，主要有四种，即步卒、材官（精选的步卒），骑士、楼船士（水兵）。兵种的确定，皆依照当地的环境来做为标准。如西北产马，则当地役男多编为骑士；平原及山地区（如巴、蜀、三河、颍川诸郡）的役男，则多编为步卒和材官；东海沿海及江湖附近地区（如庐江、丹阳、会稽等郡）的役男，则多编为楼船士。此外还有一种车士，多用于丧仪。各郡的正卒统属于太守，而由都尉指挥监督，每年八月，由太守，都尉会同各县令长丞尉一同检阅，评定高下，名曰「都试」。都试的科目，以射为主，并加试其他技术。靠水的地方，则作水师演习；边郡地方，则由太守率领马队巡行塞障。正国的正卒，则统属于相，而由中尉率领。

汉代虽没有固定的免役法，但也有若干免役的规定，由皇帝随时以诏令颁行，大致上可分为四类：一是有政治地位的人，可以免役。惠帝时，曾下诏规定官吏秩六百石以上与父母妻子同居的，或曾做过将军，都尉、二千石的，都可免役。此外，如宗室、关内侯，也曾数见于诏令。二是用以奖励才德。惠帝时，曾下诏免除「孝悌力田」者的免役。元帝时，能通一经的儒者也可免役。三是有功的人，可以免役。如高祖规定，凡曾随他入蜀汉定三秦的二千石吏，可世世免役；跟他参加平城之役的吏卒，可终身免役。宣帝时，也曾诏准霍光的后代免役。四是特殊情况下的免役。如人民九十岁以上只有一子，或是身材短小与染有疾病者，均可免役。

编制与调发

汉朝军队的编制，可分为三项：一是京师驻军及中央设立的地方常驻军队的编制，二是地方郡兵以及边郡亭障的组织，三是战时的统率系统。

京师驻军有南北军之分，其任务也不相同，南军由卫尉统领，守卫宫城。官城以内各殿舍的守卫，则以卫郎担，由郎中令统领。卫郎虽属南军系统，但其份子并非从各地的役男中抽调而来，而多半由二千石以上大官的子弟，有军官的良家子，郡国推举的孝廉的博士弟子员等来充任，此外还有不少富人子弟。这个集团可以说是皇帝最亲信的卫队，也是未来将相大臣的储备所。武帝时，于南军增置羽林、期门等兵，为皇帝的随从护卫，由光禄勋统领。

北军由中尉统领，它的职责是拱卫都城，维持京师的治安。武帝时，改中尉为执金吾，并增置八校尉（中垒、越骑、步兵、长水、射声、屯骑、胡骑、虎贲）及城门校尉，于是北军大幅扩充，东汉分北军为五校，卽屯骑、越骑、步兵、长水、射声，各由校尉率领；并另设城门校尉。

正南北两军原各有两万人，武帝时期各减为万人。京师没有长期驻扎的军队，正卒一年一轮换。同时另外组织三支侍从军（期门、羽林和羽林孤儿）。元鼎六年（前111年），又成立八支禁卫军，每支有士卒约七百人，由八个校尉率领，因称「八校尉」。这是中国历史上募兵制的开始。到东汉光武帝时期，军权进一步集中到中央。东汉时的南军，按编制卫尉以下共有官长公车司马令，卫士令、都候、宫掖门司马及丞、尉等十九人，员吏二百九十九人，卫士二千五百零七人。北军五校则有官长校尉五人，司马六人，员吏六百十四人，士兵三千五百三十六人。西汉南北军的士兵，是按兵役法自各地徵调而来，东汉则是招募来的。南北两军因是首都卫戍部队，都不负野战勤务。但从武帝起，时有以京兵远征的事，东汉因行募兵制，民不知兵，一遇有事，多以京兵出战。

东汉和帝以后，宦官权势日大，至灵帝时，更拥有自己的武力，置西园八校尉，即上军、中军、下军、典军、助军左、助军右、及左右八校尉，以宦官蹇硕为统帅。又因有皇帝的支持，原有的南北军自然无法与之为敌。朝中大臣、想要铲除宦官，甚至想仰赖地方军队，因此造成董卓之乱。

东汉时，除了京师军队北军五营、虎贲、羽林之外，中央在地方设立常驻军队，号称「营兵」。营兵主要受朝廷特别设立的都尉、校尉、谒者、将军、中郎将等指挥，并和地方太守联系不大。其中主要有黎阳营、虎牙营、雍营、护羌校尉、护乌桓校尉、度辽将军（度辽营）、匈奴中郎将、渔阳营、扶黎营、戊己校尉。

地方各郡郡兵则是平时只有千人，遇战事临时扩招，且受太守直接指挥。

屯边的戍卒，多在边防工事的亭障中服役。亭的防御设备有用土做成的高墩，为四方或六角形，上有通信用的旗杆。士墩叫烽台，又叫堠；四围有墙叫坞，坞高约合市尺一丈乡右，每边长五丈馀。烽台和坞合称为燧。发现敌人时，则于烽台上点燃烽火，敌人逼近，则据坞以守。两亭之间，相距约十里。每隔三亭以上，有特备公务人员食宿的「传舍」，设于亭的附近。备有传舍的亭的，称都亭。障较亭为大，亦有围墙，可容二百人，也可以放烽火。亭多设于长城以外，障多设于长城沿线。障的首长为障尉；燧有燧长，由亭长兼任；均受太守、都尉的指挥。

汉代遇有徵伐，多自各郡国调兵出战。战时的统率系统，最高者为大将军或将军，皆临时派定。将军之下有部，大将可统五部，每部的首长为校尉（比二千石）和军司马。部下有曲，首长为军候，曲下有屯，首长为屯长。至于地方的局部战争，则由郡都尉或县尉、乡官等统兵应战。东汉后期的刺史，也可以统兵。

至于军队的调发，其权掌握在中央政府。国家有事，由中央下令调兵，太守发兵，西汉时由郡国都尉率领，东汉时郡国都尉裁撤，太守直接率领；至于中央下令时所颁的信物，高祖时用羽檄，是一块长一央二寸的木偶，上插羽毛，表示疾速。文帝时，以虎符及竹使符调兵，虎符是铜制的虎形，竹使符是五寸长的竹片，上刻篆书。两种符都是分成两半，一半存于中央，一半存于郡国，中央欲调某一郡军队，则派使者持符前往徵调，太守勘验属实，然后指挥军队出发。但这办法只限于内部，边郡因应情形特殊，太守有自行发兵之权，汉代太守对军事所负的责任很重，如有过失，会被弹劾为「乏军兴」，其罪重则死，轻则免。

募兵制

汉代的募兵，是东汉徵兵制破坏后才普遍施行的，但早在西汉武帝时，那时便已经兼用募兵。当时对外战争频仍，徵兵不敷使用，因此必须于徵兵之外，再另外招募，八校尉的士卒，就是招募来的。此外，武帝也曾利用大量的刑徒及恶少年从军。武帝以后，募兵事由更为常见，有时甚至招募异族为兵，例如宣帝时代的羌骑，就是招募羌人组成的骑兵。

东汉光武初年，鉴于多年水旱为灾、连年战争造成户口锐减，决定采取与民休息的政策，从建武六年至建武二十三年，共计五次罢省郡国兵。虽然百姓仍有随时应召当兵的义务，但平时没有受军事训练的机会，因此士兵素质大为降低。此外郡都尉也因节省军费而停止执行训练，各郡国的役政，乃陷于停顿状态。但这种情形只限于内郡，边郡则不废都尉和都试。这种情况从光武帝之后，便一直持续下去，因此政府不得不募兵来临时补充兵源。再来官部郡徵兵机构的撤销，虽然东汉法律有徵兵的条文，但有事时临时徵兵远不如招募来得方便，因此徵兵的事，很少实行。灵帝时，黄巾乱起，屯兵不足以应付，因此大举招募，皇甫嵩、朱儁等人的平乱军队中，便有大量的募兵。其后大将军何进也会招兵买马，以制宦官。

由于东汉政府提倡儒学，人民风从，藉由经术取得高官之位，对兵事自然感到厌弃。既然人民不愿从军，募兵的数量常感到不够。而自光武帝以来，各种胡族，聚集于近塞或塞内，他们仍保持其原有的勇悍风俗，于是汉朝又招募胡人为兵。招募的胡人，大都用来守边或用来攻伐不顺的外族。光武时，匈奴南单于投降，光武移之于塞内，命其捍卫边疆，兼拒北匈奴及鲜卑。东汉一代，除南匈奴外，尚有大批投降的鲜卑、乌桓、羌，为政府招募为兵。东汉采「以夷制夷」的政策，用这些归降的胡人军队从事对外的战争。这种现象成为东汉灭亡的诱因之一。

募兵制的最大缺点，就是非常容易把国家的军队变成私人武力。因为募兵常为无家无业的人，没有家庭和产业的牵挂，也没有一定的服役期限；长官与他们长年生活在一起，只要善待之，他们自然会视长官如父兄，为之出生入死；这样一来便会形成私人为中心的中心集团，于是军阀就是这样产生的。东汉时，羌人强盛，屡次侵犯西疆，中叶之后，成为东汉边疆一个很大的威胁，政府见此情况之下，只好让大军长期防卫西边各郡。这些军队因为经常与羌人作战，战斗力很强，与内部缺乏军事训练的各郡比较起来，战斗能力自然相差很大。东汉末年，凉州爆发北宫伯玉之乱，随后马腾、韩遂等纷纷加入，汉灵帝多次派遣大军都不能平叛。凉州也成为东汉末年率先脱离汉朝中央政府控制的地区之一。而出身凉州的董卓，控制了汉朝中央政府后导致各地郡守反抗，拉开了东汉末年军阀混战的大幕。

对外关系

匈奴

西元前3世纪，匈奴汗国被冒顿单于统治，武力十分强大，多次侵犯西汉边境。前200年冬，刘邦亲率大军北上，匈奴军队佯装后退，汉军则迅速北进到平城白登山，却在白登被冒顿单于的三十万精锐骑兵包围，刘邦与汉军被包围七天七夜，最后刘邦贿赂匈奴阏氏才得以逃出重围。白登之围后，西汉元气大损，从此之后一直被迫与匈奴汗国和亲。

为了抵御匈奴的入侵，期间，西汉接续秦朝，继续扩建延长长城，其西到起蒲昌海、东至鸭绿江以南、全长近一万公里，是「中国历史上最长的长城」。景帝在位时，西汉一方面继续和亲，同时也在边境进行屯田移民，在国内则实行复马令来增加马匹，加强士卒训练并大量制造兵器，这些都是预备反抗的准备。

汉武帝即位后，于元光二年（前133年）开始对匈战争。元朔二年（前127年），汉武帝派卫青以三万铁骑击匈奴，收复河南地（新秦中）。元狩二年（前121年），又派霍去病出击匈奴，出陇西，深入匈奴两千馀里，夺得祁连山与河西走廊，切断匈奴与西羌的联络，为西汉与西域之间开辟通道。元狩四年（前119年），匈奴入右北平郡和定襄郡，武帝派卫青和霍去病大举回击，至狼居胥山而还。从此，匈奴北徙漠北一直到公元前112年又南下。

但是，汉匈之间连年的战争严重损耗两国的国力。武帝后期，汉改变国策，重新执行休养政策，而匈奴亦无力攻汉，仅能进行小规模骚扰。宣帝时期，匈奴虚闾权渠单于驾崩，随后发生五单于争立事件，分裂为五部；五单于争立事件持续多年，刚平息后又是三单于争立。其中一部首领呼韩邪单于通过臣服于汉的方式得到汉的支持，打败各个竞争对手。但其三单于之一的郅支单于逃到西方，继续与汉作对，元帝时期为汉校尉陈汤率军击斩。郅支单于被杀后，前已臣服于汉的呼韩邪单于深为惊恐，再次款塞，要求与汉和亲。前33年，呼韩邪单于到长安，汉元帝以王昭君嫁与呼韩邪单于，号宁胡阏氏，是为昭君出塞，汉匈关系因此长期友好，边境和睦，互市频繁。其他的部分匈奴部落西迁到中亚康居一带。

东汉前期，匈奴分为两部，分别为南、北匈奴。其中南匈奴立呼韩邪之孙比为单于，对汉奉藩称臣，汉在南匈奴设使匈奴中郎将，并把单于庭设于五原，以便支持和控制南匈奴。北匈奴立蒲奴为单于，在明帝在位时一度侵扰汉朝边境，被击退。章和元年，北匈奴为鲜卑所破，单于被杀，其中五十八部降汉。永元八年，车骑将军窦宪等征伐北匈奴馀部，单于遁逃，窦宪在燕然山刻石纪功而还。此后，一些北匈奴南降东汉，另外一些则向西迁徙。而北匈奴故地逐渐为鲜卑侵占。

东汉后期，附属于汉的南匈奴由于受鲜卑压迫，屯居于五原、朔方、云中、西河、美稷一带，并逐步向内郡移徙。随著时间的推移，使匈奴中郎将权力越来大，甚至擅行废立匈奴单于。。献帝时期，至曹操为丞相，分匈奴为五部，至此南匈奴不复存在。

三越

西汉立国之始，它的南边有三个华夏部族和百越部族共同建立的国家，即东瓯国、闽越国及南越国，统称三越。东瓯国据今浙江省南部，闽越国据今福建，南越国据今两广（即岭南地区的广东、广西、海南和今越南）。这三国虽然受到汉高祖册封，实际上为独立，此种情况一直持续到汉景帝为止。到了汉武帝时，汉朝国力大为增强，三个国家的国力却因为互相争战而相对衰弱，最后在汉武帝时期先后被灭，为了防止东瓯及闽越再发生叛乱，于是将二国的人民迁徙至长江与淮水地区，另外将南越国之地分为南海、苍梧、郁林、合浦、珠崖、儋耳、交趾、九真及日南九郡，自此之后，这个地区再无大乱，光武帝建武十六年（40年），南越国地区发生叛乱，汉派马援平乱，大破叛军于浪泊，此后直到东汉灭亡，汉朝南疆未再发生动乱。

西羌

羌人分布于今天青海省和甘肃省西南、四川省北部一带。秦时羌人开始强盛，他们北与匈奴的河西地区为邻，西北与西域相通。西汉初，匈奴冒顿单于势力强大，西羌臣服于匈奴，中国与西域间的通道，完全被这两个民族所隔绝。

羌在汉武帝时期被封闭在青海湖到西宁湟源县湟中县一线。「初开河西，列置四郡（河西四郡），通道玉门，隔绝羌胡，使南北不得交关。……羌乃去湟中，依西海、盐池左右。」汉宣帝时代羌汉军事对峙线在兰州，「遂寇金城。」汉光武帝时代羌汉军事对峙线在从西宁到兰州一线来回拉锯。

总地来说东汉初年羌汉军事对峙线在今天京藏高速公路偏向西宁一带拉锯，期间羌汉杂居，时有冲突，临羌县是汉羌军事对峙线最前沿。羌称帝后，羌汉形势发生巨变。羌人第一次攻入甘肃东南部。长安开始戒严，「置京兆虎牙都尉于长安，扶风读为于雍。」也就是在这个时候，羌汉军事对峙线发展到长安一带，而一部分羌军已经攻入山西上党，而甘肃省西部已经不再属于东汉。差不多在这个时候，甘肃战场与宁夏打通，羌人和匈奴可以直接联系了。

其后任尚、邓遵、马贤时代，羌人稍弱，东汉稍微恢复了甘肃东部，「帝乃复三郡。使谒者郭璜督促徙者，各归旧县，缮城郭，置候驿。既而激河浚渠为屯田，省内郡费岁一亿记。遂定安定、北地、上郡及陇西、金城常储谷粟，令周数年。」「自羌叛十馀年间，兵连师老，不暂宁息。军旅之费，转运委输，用二百四十馀亿，府帑空竭。延及内郡，边民死者不可胜数，并凉二州遂至虚耗。」东汉国家国力在汉羌战争中被大大损耗。「今三郡为未复，园陵单外。」充分说明了汉长陵等陵园直接暴露在羌人的进攻矛头下。

在这种情况下，爆发了汉羌决战。马贤、赵冲之死标志著羌军对东汉全面战略进攻的开始。

总结：由于西羌的内迁，和河西走廊、陇西当地的汉朝人时常发生冲突。最初，西北的地方官多数都残酷苛暴，导致西羌反抗此起彼伏，西羌人屠杀汉朝人，西羌人在东汉取代了北匈奴成为汉朝第一外患，西北地区尤其是关中多次沦为战场，羌人还曾一度兵进至山西河东。不但如此，刚崛起的鲜卑、南匈奴亦不时起兵南下，战乱波及关中、陕北、陕南等地。此战之后，使得关中更加荒芜，成了羌、氐、匈奴、拓跋等族的混杂区，东汉西北人口大量内迁，导致河套以南地区也成了「羌胡区」。关中地区的经济、人口一直等到北周时期才逐渐复苏。唯一幸免战乱的西北地区是凉州西部，尤其是敦煌、酒泉和张掖等郡在战争时相对稳定，此地是后来张氏前凉的根据地。

东汉与西羌的战争严重损耗汉朝的国力，成为汉朝灭亡的诱因之一。董卓就是在东汉与羌的战争中崛起的汉军将领。

西南夷

今云南、贵州两省，加上四川省的西部和南部以及甘肃省的南隅，这一片广大的地区，在汉朝初期被许多异族所盘据，汉人统称为「西南夷」，它们有的进入农业社会，有的则维持游牧生活，并且建立许多国家。武帝时期，令唐蒙由筰关入夜郎，见其君多同，给予丰厚的赏赐，并告知其汉朝的声威，说服其臣属于汉朝，夜郎愿意臣属于汉朝。元光五年（前130年），汉于夜郎及其附近之地置犍为郡；并于夜郎置夜郎县，以多同之子为令。同年，邛、筰、冉、駹等族，也希望得到汉朝的赏赐，请求成为汉朝的臣属，于是汉在其地置十馀县，由都尉统之，隶属于蜀郡。但是过了几年，西南夷屡次反叛，汉朝发动军队平乱，需要花费许多军费。最后，武帝采纳公孙弘的建议，放弃西南夷的经营，全力对付匈奴。已设的县，大都废弃。

元鼎五年（前112年），南越反叛，汉朝下令西南夷发兵帮忙徵讨，西南夷不从。隔年，汉朝派郭昌、卫广击败西南夷，在这些地方设立益州等郡。新设诸郡辖区中的各部族，皆因其旧俗而治理，不徵赋税。地方政府的开支，则由内地各郡分摊供给。西南夷至此归入汉朝疆域，西南夷内属后，仍有小规模的叛乱，终西汉之世，未发生大型动乱。王莽时才开始大乱。东汉光武帝，敉平动乱后。到东汉时期，汉朝与这些地方联系更加紧密。

朝鲜

汉高祖时，卫满朝鲜灭亡箕子朝鲜后，定都于王险，惠帝吕后时，为汉藩臣，双方平安无事数十年。汉武帝时，卫满的孙子右渠在位，对汉的态度转为强势，武帝派杨仆、荀彘率军讨伐，费时一年方能平定，汉在其地设置乐浪、玄菟、真番、临屯四郡，其中以乐浪为最重要。昭帝始元五年（前82年），汉朝撤除临屯、真番二郡，以其地合并到乐浪、玄菟。半岛上的民族，非常复杂。半岛北部，除了来自中国的朝鲜人外，尚有濊貉、沃沮等族。半岛南部，尚有辰韩、马韩、弁韩并立，通称三韩。

在玄菟郡东北今松花江上游一带，尚有一个夫馀国，高句骊人便是夫馀人的别支。元帝时，夫馀人朱蒙，率众南下至朝鲜旧壤，建高句骊国，以高为氏，逐渐侵占汉玄菟郡地。半岛南部的「三韩」地区，也慢慢发生变化，宣帝五凤元年，朝鲜遗族据辰韩地建国，号「徐罗伐」，后改称「新罗」，新罗不久便夺取弁韩。到成帝鸿嘉三年（前18年），高句骊王族据马韩地建国，号「百济」。西汉末年朝鲜半岛的形势，大致是西北部是汉乐浪郡辖区，东北大部为高句骊所据；新罗据东南部地，百济据西南部地。百济、新罗因居半岛南部，与汉朝没有什么关系，惟高句骊与汉接近，关系较密。它自建国后，对汉一直是称臣的。后来东汉之后，高句骊时叛时降，成为汉帝国的东北大患。

倭国

汉朝时期，日本列岛共有一百多个国家，皆是倭人建立的，汉人统称为倭国。倭奴则是诸倭国中的大国，它座落倭国的极南界，当在今日本南部的九州岛上。因倭奴的势力较大，且距大陆较近，所以它首先代表诸倭国与中国交通。据说当时倭人饮食以手抓取食物，并有纹身、赤足、蹲踞的习惯；男子则盛行多妻，女子则不淫不妒。同时社会安定，极少盗窃争讼的事。自汉武帝于朝鲜设四郡后，中国文化开始影响诸倭，诸倭通使于汉者达三十馀国，倭国也于此时开始对汉作岁时的贡献，纳贡的地点大概在乐浪郡。

光武初年，辽东太守祭肜威震北方，若干外族国家闻声朝献。建武中元二年（57年），当时正是日本史上的垂仁天皇时代，日本倭奴国王遣使来汉，汉赐一枚「汉倭奴国王」金印，曾于清乾隆四十九年（1784年）在九州北部发现，至今是日本的国宝。此时倭奴又于安帝永初元年（107年）和献帝建安六年（201年）两度来朝。到三国时代，双方的交流更加密切。

乌桓与鲜卑

乌桓与鲜卑均属东胡族。东胡位置在匈奴东边，其活动范围在内蒙古东部与辽宁省一带。秦汉之际，东胡逐渐衰落，因此被匈奴雄主冒顿单于击败，馀部聚居乌桓山和鲜卑山，形成后来的乌桓族与鲜卑族。汉初，二族皆臣属匈奴，武帝时，汉击破匈奴左部，徙乌桓于上谷、渔阳、右北平辽东等郡，为汉朝监视匈奴的行动，并设护乌桓校尉管理，昭帝到西汉结束为止，乌桓虽然发动一些叛乱，不过没有造成西汉太大威胁。

王莽篡汉后，因讨伐匈奴，徵乌桓兵屯代郡，并以其妻子为质。乌桓因不服水土，相率逃亡，王莽因为这样而杀害人质，乌桓决定投降匈奴。光武初年，乌桓与匈奴一同入侵汉朝，乌桓早已迁入中国塞内，造成中国北部居民，其生命与财产受到很大的侵害。建武二十年（44年），东汉派马援征讨乌桓，乌桓闻讯先行撤退。其后乌桓趁匈奴内乱之时进攻匈奴，把匈奴赶出大漠以南。东汉对乌桓的态度转趋怀柔，允许乌桓人部分移居太原关内各地，驻牧于辽东属国，再度为东汉监视匈奴，并复设护乌桓校尉管理，自此之后，乌桓为东汉保卫疆界。需要古代史料来源佐证

鲜卑居地与乌桓相接，言语风俗也与乌桓相同，但它在西汉时代，与中国没有交通。东汉光武初年，匈奴又再度强大起来，命令鲜卑、乌桓一同劫掠中国北部。建武二十一年（45年），鲜卑与匈奴入侵辽东，为辽东太守祭肜打败，鲜卑对东汉才感到畏惧。次年，匈奴南单于降汉，北单于孤立，鲜卑开始通使于东汉，东汉命令鲜卑攻击北匈奴，鲜卑因此受到东汉许多赏赐。其后经明、章二代，鲜卑均恭顺无事。不过到和帝初年，窦宪大破北匈奴后，鲜卑趁机占据其地，此后渐渐强大，而成为东汉的边患。

人口

秦末民变和楚汉战争，造成期间大量人口死亡。司马迁在《史记》中感叹：「初作难，发于陈涉；虐戾灭秦，自项氏；拨乱诛暴，平定海内，卒践帝祚，成于汉家。五年之间，号令三嬗。自生民以来，未始有受命若斯之亟也。」汉五年（前202年）人口数在1500万-1800万人左右。此后由于奉行黄老政治、与民生息，到汉武帝时期的领土扩张，人口数量大幅提升。据《汉书·地理志》的记载，汉平帝元始二年（2年）有12,233,602户，口数为59,594,978人。

由于中国历史早期农业发展集中在黄河流域，故人口密度分布为北多，南少。若以淮河、秦岭为界，北部人口占据85%以上的比例，以南人口占据不到15%的比例。人口数超过500万的司、豫、冀、兖、青、徐五州均位于黄河中下游地带，这五州的人口总数占全国的55%。首都长安周围人口密度达每平方公里1000人左右。人口数量在200万以下的有交、凉、并、朔方四州。扬、荆、益三州的主要人口分布在成都平原、南阳盆地、太湖平原和宁绍平原。

新莽末期，自然灾害频发，天凤四年（17年）估计有5600万人口，但是由于王莽改制失败和天凤元年（14年）的黄河改道导致随之而来的绿林赤眉之乱和军阀混战，造成期间大量人口死亡。至建武中元二年（57年）时，全国人口数量仅2100.7820万，仅相当于西汉元始二年的36.427%。后人口开始恢复增长。据《续汉书·郡国志五》所载，永和五年（140年），全国有户969.8630万，口4915.0220万。至永寿二年（157年），全国有户16,070,906，口50,066,856。东汉的人口分布又有变化。新莽末东汉初期，大量的中原人民为躲避战火向长江流域迁徙，南方人口升至全国四成。口数超过500万的有豫、荆、扬、益四州。荆益两州的人口都增加一倍，扬州人口也增加四分之一。南方人口增长的同时，北方大部分郡国人口减少。东汉晚期战争不断，到晋武帝太康三年（282年），全国人口又只有1885万人；只相当于125年前的三分之一。

经济

农业

从西汉开始，铁制农具已经开始成为主要的生产工具，著名的农具种类有铁犁壁、矩犁、全铁曲柄锄等。牛耕是最主要的犁地方式，最重要的犁地法是二牛抬杠。一些新式耕田法，如代田法、区田法相继诞生。国家注重兴修水利，尤以关中地区为最。著名的水渠有成国渠、六辅渠、白渠等。在雒水附近有一条龙首渠，由于附近地区土质松软易坍塌，就用凿井的方法代替地上渠道，叫做井渠，极类似于今天新疆地区的坎儿井。东汉初期，出现翻车和渴乌等水利工具，增加农业生产效率。著名的农书有《泛胜之书》，里面提到的相关技术，有效提升农作物的产量。

手工业

西汉前期，冶铁业分国营（中央政府）、官营（地方经营）和民营三种类型。当时著名冶铁家有卓王孙、南阳孔氏等。汉武帝于元狩三年收冶铁为国营，自此之后冶铁业开始衰落，但由于此对国家财政较有利，之后一直没有改变此政策。到了东汉光武帝在位时，冶铁业改由社会自营，加上水排的发明，冶铁业更加发达。铜器虽出现变少，但在两汉时期仍是重要的金属器。漆器则是两汉时期重要的工艺品。汉朝的纺织业亦有国营与民营之分，民间著名纺织业者有陈宝光妻，她是织花机的发明者。到东汉前期时，蚕桑养殖在长江流域和岭南等地开始推广，特别是巴蜀地区。蜀锦更价值连城，在三国时代甚至成为蜀汉一大财源。麻葛制品中，最出名的是产于会稽地区的越布。

File:HanHorse.jpg|吉美国立亚洲艺术博物馆馆藏 汉代马雕像

File:HK Museum of Art TST 加彩灰陶马 Painted Grey Pottery Horse Han Dynasty.JPG|香港艺术馆馆藏 汉代《加彩灰陶马》

File:Green glazed pottery dog Eastern Han 25CE 220CE.jpg|上海博物馆馆藏 东汉绿釉陶狗

File:Mawangdui silk banner from tomb no1.jpg|湖南省博物馆馆藏 马王堆一号墓T型帛画

File:Gansu Museum 2007 257.jpg|甘肃省博物馆馆藏 铜奔马

商业及贸易

西汉初期奉行重农抑商政策，不过由于实施黄老政策，对于商人的影响不大。经过文景之治后，商业势力大为篷勃发展，社会心理也随之改变，当时俗谚流传著「夫用贫求富、农不如工、工不如商」，「今法律贱商人，商人已富贵矣，尊农夫，农夫已贫贱矣」。虽然曾受到武帝「富国抑商」政策打击，西汉后期，由于汉室政权中衰，商人势力于是重新抬头。到了东汉，政府并未制定限制商人获利的法令，所以商业发展一向顺利，但也造成贫富差距急剧扩大，加深经济矛盾，东汉就在这样的情况下导致衰亡。

两汉的商业都会的分布，并没有太大的改变，商业活动以黄河流域为主，淮河流域次之，长江流域又次之。当时各都会分布的区域，可以划分为三大部：（一）关中区—以长安为中心都会，南控巴蜀，西北控天水陇西北地上郡等腹地。（二）关东黄河北岸—分为河东、河内及其相联系的燕赵区。河东区以杨、平阳为都会。河内区以温、轵为都会。燕赵区以邯郸与为都会。（三）关东黄河南岸—主要为河南区，并控驭齐鲁梁宋三楚南越及颖川南阳区。河南区以雒阳为中心都会。

两汉与西域的贸易最为盛行。。主要有两条线南道与北道。南道以敦煌为起点，出玉门关至楼兰，经大夏、安息、条支，过地中海至大秦，这条路线主要运送的货物是丝织品，所以西方人称为「丝路」。北道沿今天山南坡西行，越过葱岭北部，可抵奄蔡，并可通向大秦。这条路线主要运送的货物是貂皮，因此被称为「毛皮路」。

南越于武帝设郡后，南海的商业与交通开始蓬勃发展，当时这个地区中最大的商业都市是番禺，它是珠玑、玳瑁、果布的交易之处。其他如徐闻、龙编、也都是著名的商业城市。西汉时代的海上交通，可到达马来半岛的都元国与谌离国。东汉时，中国商船可到达锡兰岛的狮子国一带，与印度也有直接交通。因此锡兰岛与南印度的佛教，也经由海上来到中国南部传教，桓帝延熹九年（166年），罗马帝国皇帝马尔库斯·奥列里乌斯，遣使由印度洋经日南徼外来汉，贡献方物。

货币制度

西汉自建立以来，货币沿袭秦朝的半两，但是品质低劣，实际重量往往只有八铢、四铢、甚至更轻，有的薄如榆联，被称为「榆荚钱」，贵族、豪商大肆盗铸钱币，造成币制混乱。郡国铸币失控也是汉景帝时期七国之乱发生的原因之一。汉武帝即位后，一方面出于中央政府在经济管理和政治统治上需要，另一方面由于对外征伐带来的岁出增加令国库日窘，故十分重视币制问题，先后进行六次币制改革。第六次改革推行「三官五铢」，一举解决困扰西汉金融多年的私铸、盗铸问题，既稳定金融，又将汉高帝下放民间的铸币权重新统一于中央政府，于是币制得到长期稳定。五铢钱成为自汉武帝时代直到隋朝七百馀年间国家铸币的主要形式。现在汉墓中经常出土的直径约2.3公分，重量约3.5克的五铢钱，就是汉武帝时代第六次币制改革产生的「三官五铢」。

西汉末期至新朝，王莽推行的一系列币值改革一度引起币制的混乱。到东汉初期，王莽币才逐渐退出历史舞台。

土地与赋税制度

汉代的土地所有制与秦代相同，土地私有，并可自由买卖。土地所有者须向国家纳耕地税，耕地税率为亩产的十五分之一或三十分之一。人口税分为算赋和口赋。算赋是丁税，十五至五十六岁的男女每年每人纳一百二十钱（一算）。口赋是儿童税，七至十四岁的儿童每年每人纳廿钱。西汉早中期，政府积极推行「重农抑商」政策，压抑富商豪强势力，土地、农业问题曾一度稳定。到西汉后期，汉元帝废除迁徙关东豪强前往关中汉帝陵区政策，土地集中日益严重，中央朝政腐败黑暗，造成自耕农大量破产，沦为佃农。豪强庄园势力日益强大。东汉早期，虽然重新推行重农政策，却因富商豪强势力已成，而无法撼动，造成地主庄园势力的膨胀，其后东汉诸帝无力解决这个问题，加上人口不断增加，而粮食生产又没有跟上人口成长，终于爆发黄巾之乱，导致三国局面的形成。

宗教及信仰

汉朝为道教、佛教两大宗教的形成及传入期。

道教可以追溯到秦汉以前中国人固有的多神教信仰传统、巫术信仰以及神仙说的崇拜。在这三者各自发挥的影响下，另外儒家学说又与黄老思想合流，加上灾异、谶纬之说，弥漫两汉社会，为道教信仰奠定群众基础，最后促使宗教性质的道教产生，是黄老思想和神仙家紧密结合的成果，自从汉武帝罢黜百家之后，黄老思想便开始消沉，此后便被神仙家方士运用，朝向宗教方面发展。方士们将其思想拿来与他们鼓吹的神仙方术互相结合，于是老子日趋神化，时间久了便成了道教的始祖。到了东汉，黄老已经成为宗教的名称。叫做「黄老道」，不过此时还是道教的前身，直到张陵出世后，编纂经典，传道收徒，建立固定的宗教仪式和宗教组织后，道教的雏形便宣告完成。东汉末年，道教分为两大流派，一支为太平道；另外一支为天师道，亦称为五斗米道。而五斗米道内部还有一个大支派，以于吉为教主，在长江下游地区传播。

佛教在汉朝由印度经西域传入中国。根据记载，汉哀帝元寿元年（前2年）博士弟子景卢出使大月氏，其王使人口授《浮屠经》。东汉永平十年（67年），汉明帝梦见金人，于是派人去西域，迎来迦叶摩腾与竺法兰两位高僧，并且带来许多佛像和佛经，用白马驼回首都雒阳，皇帝命人修建房屋供其居住，翻译《四十二章经》。也就是现在的白马寺。因此，在中国佛教史上，多以汉明帝永平十年作为佛教传入之年。白马寺成为中国第一座佛寺。《四十二章经》，也成为中国第一部汉译佛经。马伯乐认为这些记载纯属捏造，汤用彤则认为可能有部分属实。147年安息人安世高到汉朝传教译经，167年月氏人支娄迦谶到汉朝传教译经。

巫觋活动，术数之学，这些民间礼俗迷信在汉朝社会相当普遍。比如传统禁忌形式，曾经十分严格。湖北云梦睡虎地秦简《日书》中，就有关于行归宜忌的规定。《日书》是选择时日吉凶的术数书。在总计四百二十五支简中，简文直接涉及行归宜忌的多达一百五十一支。汉武帝同样「尤敬鬼神之祀」，曾经「作画气车，及各以胜日驾车辟恶鬼」。又在皇室活动中始用「越祠鸡卜」之术。甚至在军事行动中应用巫术，「丁夫人，雒阳虞初等以方祠诅匈奴、大宛」。民间礼俗迷信对正统社会机制有修补与维护的作用。中国古代「符瑞」迷信曾经成为政治文化的特殊内容之一。西汉时，汉文帝时见黄龙，汉武帝时获白麟、宝鼎、赤雁，汉昭帝时凤凰集、神爵集，汉成帝时甘露降，都被看作体现统治成功的「嘉瑞」。

文化

两汉是中国历史上科技与文化非常辉煌的一个时期。国家也非常重视教育和学识。文翁蜀郡作石室立学堂，为地方学校之始，尔后武帝令地方郡县皆立学校，遂致「四海之内，学校如林，庠序盈门。」后汉国学犹盛，顺帝以降，中央太学增至三万馀生。汉人之学，皆重经验、积往古之学说，因当时之风习，遂有发明制作之专家。

学术思想

汉朝初建，承袭秦法，当时的学术思想界，却恢复春秋战国时代，各家并立的状态，因为秦朝灭亡后，学术思想的研究障碍已解除，虽然秦朝的「挟书律」及「妖言令」到惠帝、吕后时才废除，但实际上未废除前，政府对学术思想的研究，是不太过问的。战国时代的儒、法、道、阴阳、纵横五家，在汉朝初期依然活跃，但在中期以后，由于政府的提倡，学术界变成以研究经学为主。

汉代的治国思想。汉代在立国时用法家之法，又用道家黄老思想为主，文景时期，并辅以儒家和法家思想为法制指导思想，不仅强调无为，还注重礼与德的作用，既承认法律的重要性，又坚持约法省简，务在安民。 而从汉武帝之后，统治者又确立儒家思想成为正统思想，并辅之以法家思想为法制指导思想，其中心是「德主刑辅」，即先用德礼教化，教化无效再施之以刑罚。这种刚柔相济的治国之道，成为汉武帝以后汉王朝法制的指导思想。这一思想对后世历代王朝的立法影响很大。汉宣帝曾有名言：「汉家自有制度，本以霸王道杂之。」便是这种思想的精辟阐述。

早在秦始皇焚书坑儒所毁坏的很多文献，通过汉代学者的记录得以重现，包括五经当中的古文尚书，也是这时候发掘整理出来的。汉初的经书，全由私人传授，汉武帝采纳董仲舒的意见「罢黜百家，独尊儒术」后，经学成为学术主流，经学家也愈分愈多。由于不同学者对经书的理解与记忆有所不同，经学也被分为不同流派。宣帝时期，在太学中立学官的，《易》有三家，《书》有三家，《诗》有三家，《礼》有一家，《春秋》有两家，共十二博士。东汉初年，增加到十四博士。学者都尊崇其师以及学说，世代不替，因此学派的区分，日益严格。

两汉的儒家，虽然尊崇孔子，不过也受到阴阳学家的影响，因此他们的学说，开始出现宗教的迷信色彩。例如京房易专重卜筮，大小夏侯尚书喜论五行之说。武帝时，董仲舒治公羊，著春秋繁露一书，其中也有不少离奇的话，此外他也提出「天人感应」，敦促君主施行仁政。成帝时的刘向，治谷梁，也多次以祸福附会其说。总之，这些学者认为天降的祥瑞或灾祸，全是受到人事的影响，尤其是君王的贤愚勤怠，有非常密切的关系，由于武帝以来，君王的权力已经大为提高，唯一还有所顾忌的便是天灾异变，当时学者常使用这种论调来批评当时朝政。

西汉末年，儒学附会阴阳学说后，天象人事的比附，演变为「谶纬之学」的出现，内容更为奇特。谶纬大都出于当时人之手，而伪托为古人的著作。这种神话思想的风行，使得儒学的人文精神和实践精神遭到败坏，也造成王莽篡位的理论基础，光武帝同样因为图谶，最终建立东汉王朝，统一天下后，由于他特别笃信谶纬，在处理政务遇到纷争，犹疑不定时，常常借重谶纬来帮助决策。又在建武中元元年（56年），又曾经正式「宣布图谶于天下」，进一步确定图谶作为法定经的地位。谶纬神学的尊严得到政治权力的庇护。造成当时「儒者争学图纬，兼复附以妖言」。因此谶纬的地位，在某种意义上甚至超过经书。后来曹魏代汉，也造作谶言「代赤者，魏公子」，「鬼在山，禾女连，王天下」。利用民间谶纬迷信，以实现政权的更替。

西汉晚期，刘歆发起研讨古本经籍的运动，他根据汉代陆续发现的古文经书，如春秋左氏传、古文尚书、逸礼等，另立解说，此外他也将毛诗也列为古文，与今文家相抗衡，引起「今古文之争」，他不但提倡研究古文经书，更主张设置上述四经博士，不过为当时今文家所反对，立学官的事，终告失败。不过民间研究古文之风大盛，学者辈，明帝时的贾逵，桓帝时的马融，都以治古文名家，到东汉晚期，古文经学走向发达，今文经学日益衰微。古文学最大的贡献，是把经学从今文家的荒诞迷信的经说，引导考据训诂之途。

文学与史学

赋是汉朝流行的主要文学体裁，由《楚辞》发展而来，贾谊是为赋的开创者，他的作品《吊屈原赋》、《鹏鸟赋》等作，借物抒怀，意境深沉，同时在抒发情感之外，兼言哲理，这是文学由通俗体走向文人体的表现。贾谊的赋作气力雄劲，但文采不艳，在他之后的赋家，则完全著重于辞藻的铺陈，作品更趋文人化。武帝时代的枚乘、枚臯、东方朔，更趋向于这个方向，到司马相如的《子虚赋》、《上林赋》，这些赋作气势恢宏，代表时代精神的豪迈勇进、物质生活和精神生活的丰富多彩。西汉后期，最有名的赋作家是扬雄。东汉时期，则以班固、张衡的作品地位最高。东汉后期，长篇赋逐渐变少，各种抒情写物的短篇赋开始流行，与先前的长篇赋文辞藻华丽的风格逐渐渐行渐远，意境较为清新。

汉武帝时设立乐府，搜集民间诗歌，并令词臣制作诗歌，协以音律，即为乐府诗，乐府的句府虽然参差，但以五言最为突出，它促进五言诗的产生。乐府歌辞本来配题、配乐，各有其特定用途，其后，袭旧题旧乐而改歌辞；或仅借旧题，乐辞均改；乃至题、乐、辞均改之例日益孳多，辞与乐的关系乃渐渐疏离，最后完全无关，成为徒诗—仅供阅读的作品。其特色是诗人以极昏混乱的景、极沉重的口吻描写战争之频繁、惨烈、以及阵亡者的忠勇与悲哀，完全呈现现实世界的不堪，给人极为强烈的震撼。乐府诗为中国古典诗注入写实的精神，建构写实传统坚实的基础。代表作品为《陌上桑》与《孔雀东南飞》。

古诗与乐府诗同起源于汉代，主流形式是五言，五言之外，也有七言的形式。大抵由乐府诗演变而成。两汉时代处于发展阶段，到东汉末年才趋于极盛。其特色为：章法上，句数不定，可自由伸缩，不受限制，但通常为双数句；韵法上，以连句韵及隔句韵为常见，可自由换韵，用韵较宽。代表作品为：东汉班固的《咏史诗》，象徵五言诗的正式成立、《古诗十九首》，朴实自然，感伤抒情，为五言诗最早成熟的作品，后来在魏晋南北朝更为篷勃发展，曹魏曹丕的《燕歌行》，象徵七言诗的正式成立，南朝宋鲍照以后才逐渐发展。

汉代的散文，继承先秦诸子系统的论说理文，作品特色是大段铺排，气势雄浑。句式厚重朴实又不失变化，最具代表作者仍是贾谊。他的《治安策》，对文帝、景帝、武帝三朝政治情况的发展有著深厚的影响，仅以文章而论，其辞理的畅达，剖析的深刻，以及气势的高昂，为散文开创独树一格的境界。他的另一本著作《过秦论》，体裁与赋接近，这篇论成为魏晋六朝人著论的典范。其他有名的书策作者有晁错、董仲舒、司马迁等。晁、董的作品，皆流畅适切；司马迁的文章，与当时辞藻华丽的风格与众不同，以「辨而不华，质而不俚」的手法建立自家的风格，他的最具代表作品为《报任少卿书》，字句间充满情感，也是汉代的散文名作之一。

在史学方面，汉朝史官司马谈之子司马迁的《史记》是中国历史上第一部纪传体通史，也是二十四史中的第一部，为以后两千年正史的编纂提供规范。全书分为十二本纪、十表、八书、卅世家、七十列传，共一百卅篇，五十二万六千五百字。班固所编写的《汉书》分为十二纪、八表、十志、七十列传。全书体例仿效《史记》，惟改「书」为「表」，废「世家」入「列传」，还开创刑法、五行、地理、天文、艺文四志和《百官公卿表》。《汉书》是中国历史上第一部内容完整的断代史。更是成为以后历代王朝撰写本朝历史的范本。而两汉时期其他的史书还有《东观汉记》、《汉纪》和《吴越春秋》等。很多西方学者认为，汉代的作家所开创的史学标准，直到18世纪都一直领先于世界。

书法

汉代的主要书写文字为隶书，从秦代隶书发展而来。「隶书」又称「佐书」、「古隶」、「今隶」、「八分书」。隶书具有以下特色：一、隶书的最大特点是由直线构成，它不像小篆由相互连接的圆转，有时又有逆向书写的线条组成，而是由散开而平直方折的笔画构成，凡逆笔都变为顺笔，书写起来不仅顺手，而且快速。二、笔画难以呈现具体的形象，古文字象形的特质从此消失，而且形体多已不合六书原则。三、汉字发展至隶书已经彻底「符号化」。隶书对大、小篆加以省略、简化，结构单纯许多，就是做为日常生活书写工页，不啻为一大进步。另外篆隶形成中国书法艺术主流，汉代时期，隶书渐渐取代小篆成为主要书写字体，隶书的出现奠定现代汉字字形结构的基础，成为古今文字的分水岭书法。隶书经过两汉的发展后，又发展出另一种字体「楷书」，最后成熟于唐代。

艺术及工艺品

汉代的艺术活动，继承和发扬先秦多种形式艺术与技术的基础，造形意识从萌芽逐渐趋于成熟；西域与佛教外来艺术的传入，更丰富汉代绘画与雕刻的题材与技法，表现出极高的原创性。无论陶兵马俑、歌舞俑还是画像石、画像砖，工匠懂得雕刻这些作品的人、神、兽。工匠除了用特殊的艺术手法塑造和描画古代著名人物、神仙妖魔和珍禽异兽，也能以写实的手法描绘当时生活中的达官贵人、文臣武将乃至工匠农夫。

汉代陶俑的最高水平表现在歌舞俑上。西安出土的舞女俑，扭动腰肢，挥舞双臂，挪动舞步，正在轻歌曼舞。舞女身穿舞裙，纤细的腰上束著宽腰带，两条宽大的舞袖随风摆动，像长而轻的红绸。这座塑像体态轻盈，动作优美富于动感；舞衣和长袖柔软而飘，显得非常生动。从歌舞俑的造型来看，汉代工匠已经确实掌握人像塑造的技巧，尤其是人物在运动时，肩、胸、腰、腿的变化关系，给人像注满活跃的生机。汉代最具代表性的石雕为霍去病陵墓石雕。内部有马踏匈奴、卧马、跃马、卧虎、卧象、卧牛、石蛙、石鱼、野人、野猪、石蟾、母牛与小牛，人与熊等造型。。麻浩崖墓的石雕佛像是中国最早的佛教造像之一。由于近代以来，汉代青铜器大量出土。这些青铜器有两个特点：一、青铜器出土的地域非常广大，除了文化发达的黄河和长江中下游地区外，偏远的云南、贵州、广东等地，也发现精美的青铜器。二、青铜器的种类比较齐全，既有皇亲国戚墓葬里的豪华器具，也有一般墓葬里的各式生活用品，还有云南、贵州等地各民族的具有充满地方特色的青铜器。

绘画品类多为帛画、壁画、画像石、画像砖。

汉朝帛画作品极多，然而至今已几乎无存，唐朝张彦远的《历代名画记》就指出汉朝帛画数量繁多，然而经天灾人祸后毁坏极为严重。现在能见到的汉代帛画作品是出自汉墓的「非衣」、「铭旌」（旌幡）等随葬品。这是时下所见最早的记录现实生活的大型绘画作品。惜剥损较重，只能观其大略。最完整的为马王堆汉墓出土的帛画，描绘墓主人的地上和地下生活。而长沙楚墓出土的帛画《龙凤仕女图》，是中国最早绘画作品之一。西汉壁画的幻想气氛相当浓厚，从已发现的雒阳墓室壁画来看，题材多集中于青龙、白虎、朱维等方位神，荷花，灵芝等仙草，还有日月星象、后龙升天、乘风成仙等神话内容，其风格与战国帛画有承袭关系。东汉墓室壁画虽然以仍然以升天、避邪、鬿福为主要内容，但是加强绘画的人文因素，表现生活的场景明显增多。画像石在汉代陵墓地面建筑的石阙、石亭祠的壁面上，地下建筑墓室的石构件上，往往雕刻出各种人物故事、生活过程和动植物形象，人们一向称之为「画像石」。汉代画像砖的数量上虽然没有比画像石多，但仍有其历史意义与艺术价值。汉代画像砖是由战国和秦代的瓦当、空心砖上的画像演变而来的。

表演艺术

西汉初年，先秦雅乐已多数失传，但民间音乐在上层社会上中颇为盛行。他们尤其喜爱楚歌。，楚汉战争末期，西楚霸王陷入「四面楚歌」的困境，对著虞姬唱出《垓下歌》：「力拔山兮气盖世，时不利兮骓不逝，骓不逝兮可奈何」。张骞通西域后，把西域的摩诃兜勒曲和蒙古的北狄乐带回中国，当时乐官李延年据以制成「新声二十八解」，听到的人都大受感动。从此，中国的音乐在民间音乐和外族音乐的互相交融下更加蓬勃发展。从这个时侯开始，中国音乐有古乐和胡乐之分。古乐是指上古以来的传统的本土音乐，胡乐则指从外族胡人吸收的音乐。另外汉武帝时设乐府，采集许多民间歌谣与外来歌曲后，在东汉末年，出现琴曲《垓下歌》，表现出中国古代音乐的阳刚之美。

汉代舞蹈是以楚舞与中原舞蹈、中原与西域舞蹈的结合为特色。它改变先秦以来纵向承袭为主的格局，开辟纵横吸收、交流、结合发展的新局面。由于西域和西南越等少数民族乐舞、杂技、幻术的传入，表演性质舞蹈技艺的大幅提高，著名舞蹈作品和舞人的出现，乐府对民间乐舞的广泛采集，舞蹈表演活动普遍兴盛起来，出现中国历史上第一个舞蹈艺术发展的高潮。

中国戏剧在汉代处于发展阶段，汉代民间的各种演出总称为「百戏」，包括歌舞、杂技、武术等各类伎艺形式。秦二世就有「角抵」戏，到了汉朝蔚为风行。张衡《西京赋》描绘，就有角抵戏，提到「东海黄公」，「戏」里一个演员扮黄公，以红绸束发，佩赤金刀；一个演员扮成猛虎。博斗的结果，黄公被虎咬死。表演为代表体，显示出简单的戏剧性，可以视为中国戏剧的胚胎。

建筑

汉代在中国古代建筑史上，是承先起后的时代。汉代建筑有以下特色：一、布局和结构均匀、对称。二、门窗变化自由，有多种样式出现。三、顶部舒展而优美，基部气派而稳固。四、常分利用其他造型艺术，使绘画、雕塑等各方面艺术装饰于建筑。五、木料的框架总是显露出，建筑物的基本轮廓。六、城市规画严谨方整。七、园林布置灵巧别致。

汉代闻名于世的建筑，如：两都长安、雒阳和成都的建设，大量宫室、离宫、苑囿的兴建，长城防御体系的延伸与修缮，大规模营造陵墓、坛庙等等。其面积广大、数量亦多，达到前世前所未有的地步，形成中国建筑发展史上的高峰。汉代生产技术的发展和铁工具的大量使用，对建筑上的材料与应用，甚有帮助。

科技

数学

公元前一世纪的《周髀算经》及东汉初年的《九章算术》则是数学领域的杰作。其中，《九章算术》是战国、秦、汉古代社会创立并巩固时期数学发展的总结，列有分数四则运算、今有术（西方称三率法）、开平方与开立方（包括二次方程数值解法）、盈不足术（西方称双设法）、各种面积和体积公式、线性方程组解法、正负数运算的加减法则、勾股形解法（特别是勾股定理和求勾股数的方法）等筹算方法，形成一个以筹算为中心、与古希腊数学完全不同的独立体系。1983年至1984年，《算数书》在湖北江陵张家山汉墓中出土，《算数书》的发现，对《九章算术》的完成，有著直接的影响，也改写中国古代数学史，将中国古代数学的历史推前三百年。

天文学

在科技方面，东汉张衡制成世界上第一台能够感知地震的地动仪，另外撰有《灵宪》一书，解释天体演运。前104年，司马迁、唐都、落下闳等人制定的《太初历》第一次将二十四节气订入历法。85年，又改用《四分历》。

医学

两汉出现许多名医。西汉的淳于意、东汉的张仲景、华佗等等。西汉淳于意，留下25例病历纪录，对治愈和不治都有客观的分析，在中国古代医学史上，具有创始的意义。张仲景因《伤寒杂病论》而被尊为「医圣」。而史书记载华佗更是世界上最早采用全身麻醉的医师（华佗是否真有其人仍受到史学家陈寅恪等人的质疑）。俞跗运用人体解剖术治病。

《神农本草经》是这一时期著名的药典，共收录药物365种，分上、中、下三品，上品叙述滋补药物，中品叙述滋补和治病两种性能的药物，下品是专门治病的药物，这为中国后世的药物分类法提供一定的参考。针灸也得到突破性发展，东汉前期的《黄帝明堂经》，初步建构传统的腧穴学，用来服务于针灸临床。与《黄帝明堂经》同时问世的《难经》，提出「命名」的新说，进一步确立阴阳五行学说对传统医学理论的指导地位。

农学

汉代出现不少农学著作，其中以《泛胜之书》与《四民月令》最为著名。

《泛胜之书》是中国历史上第一部完整的农学著作。该书讲及当时的耕作的基本原则、播种日期、种子处理、个别作物的栽培、收获、留种和贮藏技术、区种法等。泛氏的农学成就在汉代产生深远的影响。东汉末年郑玄注《周礼》和《礼记》，都曾经引用「泛胜之术」和《泛胜之书》。唐朝人贾公彦《周礼疏》：「汉时农书有数家，《泛胜》为上。」，成书于二世纪中期，叙述田庄从正月直到十二月中的农业活动，对古时谷类、瓜菜的种植时令和栽种方法有所详述，亦有篇章介绍当时的纺绩、织染和酿造、制药等手工业。

工艺技术

汉代也是中国最早发明瓷器烧造的时代。这个时期还发明蒸馏法、水力磨坊、现代马轭和肚带的原型、漆器、用于冶金的往复式活塞风箱、出现于汉末的独轮车、水车和吊桥。造船已经采用船尾柱舵。两汉时期，中国的冶炼技术也有长足的发展和进步，铸钱技术成熟，如三铢钱、五铢钱等。彩绘工艺独特，如马王堆所出土的帛书彩绘，各种生活用品齐全，如有「汉代魔镜」之称的铜镜，煮盐技术也不断提高，两汉出现蒸馏酒，酿酒水平臻于完美。农业技术大幅度提高，东汉早期出现水排等新式灌溉工具。

纸的发明与传播

西汉中后期，宫廷内已出现一种丝质的纸，叫做赫蹏。在东汉，汉和帝时（105年），宫内宦官蔡伦改进造纸术，大大降低造纸成本，取代简帛成为主要的书写材料。造纸术在西元3世纪后传入朝鲜半岛和日本，在751年发生的怛罗斯之战后又传入中亚，之后通过阿拉伯诸国进入北非与欧洲，改变世界文明史。

交通

汉朝社会频繁的移动行为，成为商业发展有利的条件，加速物资的流通速度，「农商交易，以利本末」，因而使得经济生活表现出前所未有的活力。当时「重装富贾，周流天下，道无不通」，「千里游赦，冠盖相望，乘坚策肥」，「船车贾贩，周于四方」，「东西南北，各智巧」。以繁忙的移动行为为基础的民间自由贸易，冲破政府抑商政策的多重限制，对于秦汉经济的繁荣表现出显著的历史作用。

另一方面，交通建设的发达，对于汉朝政权统一也有所助益，有的学者曾经指出：「交通的便利，行旅安全的保障，商运的畅通，驿传制度的方便，这些因素都使汉代的人民得以免除自身的地域中心之见，他们的所见所闻比较全面且充实，知识容易传播。汉代上层阶级大多走过许多地方，因此对于「天下」全貌了解得较为清楚，也加强他们对于统一的信心。这一点不仅影响到当时人政治生活心理的健康，而且能巩固全国文化的统一性。

交通建设技术性的进步，除了表现在道路和运河的建设外，车辆和舟船的普及和运输动力的改良，也具有重要的意义。在这一段时间。「鹿车」制作简易，偶尔也可以用来运货和载人，战国时期发明的双辕车，汉代民间社会也开始普遍使用。由于畜牧业的发展，马、牛、骆驼等牲畜，广泛作为车辆动力的牵引来源，这些物品与动物的应用，为当时的生活带来不少的方便。

社会

两汉均是初期经历战争，天下残破，经济凋敝，初期的皇帝往往会自奉节约，以身作则，社会风气较为俭仆，不过随著时间的推移，当政治安定、经济发展、社会富裕后，这时的皇帝没有继续维持节俭风气，甚至起来带头放纵享乐，于是奢侈之风便会由上而下蔓延，社会风气自然会转向浮华与奢靡，而造成严重的社会危机，而导致王朝的解体。

汉代社会根据政治、经济、法律地位及享受特权的多寡，社会民户可以划分为「贵」、「良」、「贱」三个等级。「贵」包括皇帝及其宗室、外戚、军功后裔等。这个等级高居社会上层，掌握统治权力，享受很大特权。「良」包括豪族地主、商人地主、广大的自耕农和半自耕农。这个等级具有自由身份，虽然财产贫富悬殊很大，不过一样处在被统治地位，没有享受到多少特权。「贱」包括豪强底下依附民、宾客、奴婢等，这个等级的最大特点是人身自由受到限制，处在被国家或豪强大族严格管理和控制的地位。

汉代的社会生活方面，贵族人士穿著长袖的袍服，并穿戴头巾，平时收取田租为主，他们得以养尊处优，进行其他的娱乐活动，儒学成为中国文化的主流后，让其子弟研习经学，将势力扩散至政治地位上，于是土地兼并现象便难以阻止且日益严重，一般平民则穿著睡衣宽松褐和续鼻裤，偶尔还加一件及膝之短袍。一般以小家庭为最基本的经济组织，但种田时需要邻里的合作。主要的农作物为米及稷黍。妇女以蚕桑为常业，由于大部分收入要缴交给地主，因此仅能勉强维持生活，当政府给予傜役过重或遇到天灾人祸，这时农民不是依附豪强为奴，就是铤而走险发起革命。

汉代延续秦代，以皇帝为核心，以郡县制为基础的专制主义中的中央集权制正式成为主要的政治制度；地主经济取代领主制在统一国家范围内得以确其主导地位；「书同文，行同论」、「罢黜百家，独尊儒术」的文化思想统一等，这些都成为中国两千年封建社会开创先河。在社会结构上，皇帝、皇室贵族及异姓贵族、官僚士人、平民、奴婢贱民之类的等级集团，大体形成。汉代土地兼并、农民起义及社会周期性动荡等社会现象，都在后代各王朝不断重演。

西汉立国，以军事功臣作为统治集团的核心，战争中「攻城先登」与「趣功战疾」者得以立功封候。战争的特殊背景对社会生活心态产生深刻的影响，所谓「剽轻」、「剽疾」的节奏风格，一时在当代文化心理比较中居于显著的优势。接著在文景时代视社会背景，实行宽仁之政，政府对秦时苛急之政深切反省，以「无为」原则加以改变。但是「无为」并不代表消极怠惰。其实汉文帝和汉景帝二人本身是相当勤政的。那时政府鼓励「勤身从事」，文景之世所谓「天下翕然，大安殷富」。汉武帝亲政后，以武力征讨四方，开疆拓土，尚武之风大起，影响到社会节奏而转为紧凑。一时「有气敢狂」之士多以「用善骑射」而得功名。战争背景所启动的勇进精神对社会风气的影响，可以说一直持续到西汉结束为止，虽外西汉有「轻侠」之称。西汉官吏尹赏曾以严厉手段打击威胁治安的「长安中轻薄少年恶子」。西汉「少年」好勇斗狠，激进豪放的性格特徵，代表时代精神的某种倾向。

东汉立国，社会风气有所转变。社会生活节奏趋于舒缓，由于光武帝、明帝、章帝三朝推崇儒学，民间学子争相学习儒学，儒学正统对民间所谓「轻」的风习，一向持否定的态度。儒者讲究安详凝重，而鄙视轻狂疏放，另外马援侄子马严、马敦「通轻侠客」。马援曾在交趾前线写信提醒他们，不要仿效侠者的行为，此举不会得到社会的尊重，以致「陷为天下轻薄子，所谓画虎不成反类犬」。也以「轻薄」指违背儒学生活的行为倾向。以「轻」为特徵的生活节奏当时受到社会的非议。而东汉时期北边军事形势已经发生重大的变化，「匈奴既分，羽书怖闻」，南疆蛮夷也「往化既孚，改襟输宝」，在外患压力减轻之下，光武帝中期后以后，国家无战争，于是东汉长期以来是轻武备而重文治，而「专事经学」，社会上弥漫著淳美的政教之风，并且士人也开始轻视武人。

汉代的妇女地位，远比后世多数朝代来的高。吕后曾把持朝政十五年，东汉时期，临朝太后多达六位，「多女主临朝，不得不用其父兄子弟，以寄腹心，于是权势太盛。」，造成外戚势力一再抬头的原因。汉代贵族妇女在婚姻关系和家庭生活中占据较高地位，也留下深刻的历史烙印。「使男事女，夫诎于妇」的情形在民间也有表现。妇女有较高的社会地位，在有些地区甚至长期成为一种民俗特徵。汉代寡妇不受约束，西汉丞相陈平的妻子，嫁给陈平之前曾五次守寡。在婚姻离异时也可以采取主动，同样是汉代妇女的权利。但在刘向、班固、班昭等人提倡从一而终情况下东汉时期恪守贞节的女性人数较西汉时期有了大幅的增加，越来越多的妇女开始自动守节。汉代文化融合多种文化因素初步形成的时代，儒学礼制尚未能规范所有的社会层面，「夫为妻纲」的性别统治局面也尚未成型，于是存在「妇人尊贵」的现象。

君主年表

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注释

Etymology

According to the Records of the Grand Historian, after the collapse of the Qin dynasty the hegemon Xiang Yu appointed Liu Bang as prince of the small fief of Hanzhong, named after its ___location on the Han River (in modern southwest Shaanxi). Following Liu Bang's victory in the Chu–Han Contention, the resulting Han dynasty was named after the Hanzhong fief.

History

Western Han

China's first imperial dynasty was the Qin dynasty (221–207 BC). The Qin united the Chinese Warring States by conquest, but their regime became unstable after the death of the first emperor Qin Shi Huang. Within four years, the dynasty's authority had collapsed in the face of rebellion. Two former rebel leaders, Xiang Yu (d. 202 BC) of Chu and Liu Bang (d. 195 BC) of Han, engaged in a war to decide who would become hegemon of China, which had fissured into 18 kingdoms, each claiming allegiance to either Xiang Yu or Liu Bang. Although Xiang Yu proved to be an effective commander, Liu Bang defeated him at the Battle of Gaixia (202 BC), in modern-day Anhui. Liu Bang assumed the title "emperor" (huangdi) at the urging of his followers and is known posthumously as Emperor Gaozu ( BC). Chang'an (known today as Xi'an) was chosen as the new capital of the reunified empire under Han.

At the beginning of the Western Han (西汉 Xīhàn), also known as the Former Han (前汉 Qiánhàn) dynasty, thirteen centrally controlled commanderies—including the capital region—existed in the western third of the empire, while the eastern two-thirds were divided into ten semi-autonomous kingdoms. To placate his prominent commanders from the war with Chu, Emperor Gaozu enfeoffed some of them as kings.

By 196 BC, the Han court had replaced all but one of these kings (the exception being in Changsha) with royal Liu family members, since the loyalty of non-relatives to the throne was questioned. After several insurrections by Han kings—the largest being the Rebellion of the Seven States in 154 BC—the imperial court enacted a series of reforms beginning in 145 BC limiting the size and power of these kingdoms and dividing their former territories into new centrally controlled commanderies. Kings were no longer able to appoint their own staff; this duty was assumed by the imperial court. Kings became nominal heads of their fiefs and collected a portion of tax revenues as their personal incomes. The kingdoms were never entirely abolished and existed throughout the remainder of Western and Eastern Han.

To the north of China proper, the nomadic Xiongnu chieftain Modu Chanyu ( BC) conquered various tribes inhabiting the eastern portion of the Eurasian Steppe. By the end of his reign, he controlled Manchuria, Mongolia, and the Tarim Basin, subjugating over twenty states east of Samarkand. Emperor Gaozu was troubled about the abundant Han-manufactured iron weapons traded to the Xiongnu along the northern borders, and he established a trade embargo against the group.

In retaliation, the Xiongnu invaded what is now Shanxi province, where they defeated the Han forces at Baideng in 200 BC. After negotiations, the heqin agreement in 198 BC nominally held the leaders of the Xiongnu and the Han as equal partners in a royal marriage alliance, but the Han were forced to send large amounts of tribute items such as silk clothes, food, and wine to the Xiongnu.

Despite the tribute and a negotiation between Laoshang Chanyu ( BC) and Emperor Wen ( BC) to reopen border markets, many of the Chanyu's Xiongnu subordinates chose not to obey the treaty and periodically raided Han territories south of the Great Wall for additional goods. In a court conference assembled by Emperor Wu ( BC) in 135 BC, the majority consensus of the ministers was to retain the heqin agreement. Emperor Wu accepted this, despite continuing Xiongnu raids.

However, a court conference the following year convinced the majority that a limited engagement at Mayi involving the assassination of the Chanyu would throw the Xiongnu realm into chaos and benefit the Han. When this plot failed in 133 BC, Emperor Wu launched a series of massive military invasions into Xiongnu territory. The assault culminated in 119 BC at the Battle of Mobei, when Han commanders Huo Qubing (d. 117 BC) and Wei Qing (d. 106 BC) forced the Xiongnu court to flee north of the Gobi Desert, and Han forces reached as far north as Lake Baikal.

After Wu's reign, Han forces continued to fight the Xiongnu. The Xiongnu leader Huhanye Chanyu ( BC) finally submitted to the Han as a tributary vassal in 51 BC. Huhanye's rival claimant to the throne, Zhizhi Chanyu ( BC), was killed by Han forces under Chen Tang and Gan Yanshou (甘延寿) at the Battle of Zhizhi, in modern Taraz, Kazakhstan.

In 121 BC, Han forces expelled the Xiongnu from a vast territory spanning the Hexi Corridor to Lop Nur. They repelled a joint Xiongnu-Qiang invasion of this northwestern territory in 111 BC. In that same year, the Han court established four new frontier commanderies in this region to consolidate their control: Jiuquan, Zhangyi, Dunhuang, and Wuwei. The majority of people on the frontier were soldiers. On occasion, the court forcibly moved peasant farmers to new frontier settlements, along with government-owned slaves and convicts who performed hard labor. The court also encouraged commoners, such as farmers, merchants, landowners, and hired laborers, to voluntarily migrate to the frontier.

Even before Han's expansion into Central Asia, diplomat Zhang Qian's travels from 139 to 125 BC had established Chinese contacts with many surrounding civilizations. Zhang encountered Dayuan (Fergana), Kangju (Sogdiana), and Daxia (Bactria, formerly the Greco-Bactrian Kingdom); he also gathered information on Shendu (Indus River valley of North India) and Anxi (the Parthian Empire). All of these countries eventually received Han embassies. These connections marked the beginning of the Silk Road trade network that extended to the Roman Empire, bringing Han items like silk to Rome and Roman goods such as glasswares to China.

From roughly 115 to 60 BC, Han forces fought the Xiongnu over control of the oasis city-states in the Tarim Basin. Han was eventually victorious and established the Protectorate of the Western Regions in 60 BC, which dealt with the region's defense and foreign affairs. The Han also expanded southward. The naval conquest of Nanyue in 111 BC expanded the Han realm into what are now modern Guangdong, Guangxi, and northern Vietnam. Yunnan was brought into the Han realm with the conquest of the Dian Kingdom in 109 BC, followed by parts of the Korean Peninsula with the Han conquest of Gojoseon and colonial establishments of Xuantu Commandery and Lelang Commandery in 108 BC. In China's first known nationwide census taken in 2 AD, the population was registered as having 57,671,400 individuals in 12,366,470 households.

To pay for his military campaigns and colonial expansion, Emperor Wu nationalized several private industries. He created central government monopolies administered largely by former merchants. These monopolies included salt, iron, and liquor production, as well as bronze-coin currency. The liquor monopoly lasted only from 98 to 81 BC, and the salt and iron monopolies were eventually abolished in early Eastern Han. The issuing of coinage remained a central government monopoly throughout the rest of the Han dynasty.

The government monopolies were eventually repealed when a political faction known as the Reformists gained greater influence in the court. The Reformists opposed the Modernist faction that had dominated court politics in Emperor Wu's reign and during the subsequent regency of Huo Guang (d. 68 BC). The Modernists argued for an aggressive and expansionary foreign policy supported by revenues from heavy government intervention in the private economy. The Reformists, however, overturned these policies, favoring a cautious, non-expansionary approach to foreign policy, frugal budget reform, and lower tax-rates imposed on private entrepreneurs.

Wang Mangs reign and civil war

Wang Zhengjun (71 BC – 13 AD) was first empress, then empress dowager, and finally grand empress dowager during the reigns of the Emperors Yuan ( BC), Cheng ( BC), and Ai ( BC), respectively. During this time, a succession of her male relatives held the title of regent. Following the death of Ai, Wang Zhengjun's nephew Wang Mang (45 BC – 23 AD) was appointed regent as Marshall of State on 16 August under Emperor Ping ( AD).

When Ping died on 3 February 6 AD, Ruzi Ying (d. 25 AD) was chosen as the heir and Wang Mang was appointed to serve as acting emperor for the child. Wang promised to relinquish his control to Liu Ying once he came of age. Despite this promise, and against protest and revolts from the nobility, Wang Mang claimed on 10 January that the divine Mandate of Heaven called for the end of the Han dynasty and the beginning of his own: the Xin dynasty (9–23 AD).

Wang Mang initiated a series of major reforms that were ultimately unsuccessful. These reforms included outlawing slavery, nationalizing land to equally distribute between households, and introducing new currencies, a change which debased the value of coinage. Although these reforms provoked considerable opposition, Wang's regime met its ultimate downfall with the massive floods of AD and 11 AD. Gradual silt buildup in the Yellow River had raised its water level and overwhelmed the flood control works. The Yellow River split into two new branches: one emptying to the north and the other to the south of the Shandong Peninsula, though Han engineers managed to dam the southern branch by 70 AD.

The flood dislodged thousands of peasant farmers, many of whom joined roving bandit and rebel groups such as the Red Eyebrows to survive. Wang Mang's armies were incapable of quelling these enlarged rebel groups. Eventually, an insurgent mob forced their way into the Weiyang Palace and killed Wang Mang.

The Gengshi Emperor ( AD), a descendant of Emperor Jing ( BC), attempted to restore the Han dynasty and occupied Chang'an as his capital. However, he was overwhelmed by the Red Eyebrow rebels who deposed, assassinated, and replaced him with the puppet monarch Liu Penzi. Gengshi's distant cousin Liu Xiu, known posthumously as Emperor Guangwu ( AD), after distinguishing himself at the Battle of Kunyang in 23 AD, was urged to succeed Gengshi as emperor.

Under Guangwu's rule the Han Empire was restored. Guangwu made Luoyang his capital in 25 AD, and by 27 AD his officers Deng Yu and Feng Yi had forced the Red Eyebrows to surrender and executed their leaders for treason. From 26 until 36 AD, Emperor Guangwu had to wage war against other regional warlords who claimed the title of emperor; when these warlords were defeated, China reunified under the Han.

The period between the foundation of the Han dynasty and Wang Mang's reign is known as the Western Han (西汉 Xīhàn) or Former Han (前汉 Qiánhàn) (206 BC – 9 AD). During this period the capital was at Chang'an (modern Xi'an). From the reign of Guangwu the capital was moved eastward to Luoyang. The era from his reign until the fall of Han is known as the Eastern Han or Later Han (25–220 AD).

Eastern Han

The Eastern Han (东汉 Dōnghàn), also known as the Later Han (后汉 Hòuhàn), formally began on 5 August AD 25, when Liu Xiu became Emperor Guangwu of Han. During the widespread rebellion against Wang Mang, the state of Goguryeo was free to raid Han's Korean commanderies; Han did not reaffirm its control over the region until AD 30.

The Trưng Sisters of Vietnam rebelled against Han in AD 40. Their rebellion was crushed by Han general Ma Yuan (d. AD 49) in a campaign from AD 42–43. Wang Mang renewed hostilities against the Xiongnu, who were estranged from Han until their leader Bi (比), a rival claimant to the throne against his cousin Punu (蒲奴), submitted to Han as a tributary vassal in AD 50. This created two rival Xiongnu states: the Southern Xiongnu led by Bi, an ally of Han, and the Northern Xiongnu led by Punu, an enemy of Han.

During the turbulent reign of Wang Mang, China lost control over the Tarim Basin, which was conquered by the Northern Xiongnu in AD 63 and used as a base to invade the Hexi Corridor in Gansu. Dou Gu (d. 88 AD) defeated the Northern Xiongnu at the Battle of Yiwulu in AD 73, evicting them from Turpan and chasing them as far as Lake Barkol before establishing a garrison at Hami. After the new Protector General of the Western Regions Chen Mu (d. AD 75) was killed by allies of the Xiongnu in Karasahr and Kucha, the garrison at Hami was withdrawn.

At the Battle of Ikh Bayan in AD 89, Dou Xian (d. AD 92) defeated the Northern Xiongnu chanyu who then retreated into the Altai Mountains. After the Northern Xiongnu fled into the Ili River valley in AD 91, the nomadic Xianbei occupied the area from the borders of the Buyeo Kingdom in Manchuria to the Ili River of the Wusun people. The Xianbei reached their apogee under Tanshihuai (檀石槐) (d. AD 180), who consistently defeated Chinese armies. However, Tanshihuai's confederation disintegrated after his death.

Ban Chao (d. AD 102) enlisted the aid of the Kushan Empire, occupying the area of modern India, Pakistan, Afghanistan, and Tajikistan, to subdue Kashgar and its ally Sogdiana. When a request by Kushan ruler Vima Kadphises for a marriage alliance with the Han was rejected in AD 90, he sent his forces to Wakhan (Afghanistan) to attack Ban Chao. The conflict ended with the Kushans withdrawing because of lack of supplies. In AD 91, the office of Protector General of the Western Regions was reinstated when it was bestowed on Ban Chao.

Foreign travelers to Eastern-Han China include Buddhist monks who translated works into Chinese, such as An Shigao from Parthia, and Lokaksema from Kushan-era Gandhara, India. In addition to tributary relations with the Kushans, the Han Empire received gifts from the Parthian Empire, from a king in modern Burma, from a ruler in Japan, and initiated an unsuccessful mission to Daqin (Rome) in AD 97 with Gan Ying as emissary.

A Roman embassy of Emperor Marcus Aurelius ( AD) is recorded in the Weilüe and Hou Hanshu to have reached the court of Emperor Huan of Han ( AD) in AD 166, yet Rafe de Crespigny asserts that this was most likely a group of Roman merchants. In addition to Roman glasswares and coins found in China, Roman medallions from the reign of Antoninus Pius and his adopted son Marcus Aurelius have been found at Óc Eo in Vietnam. This was near the commandery of Rinan (also Jiaozhi) where Chinese sources claim the Romans first landed, as well as embassies from Tianzhu (in northern India) in the years 159 and 161. Óc Eo is also thought to be the port city "Cattigara" described by Ptolemy in his Geography ( AD) as lying east of the Golden Chersonese (Malay Peninsula) along the Magnus Sinus (i.e. Gulf of Thailand and South China Sea), where a Greek sailor had visited.

Emperor Zhang's ( AD) reign came to be viewed by later Eastern Han scholars as the high point of the dynastic house. Subsequent reigns were increasingly marked by eunuch intervention in court politics and their involvement in the violent power struggles of the imperial consort clans. In 92 AD, with the aid of the eunuch Zheng Zhong (d. 107 AD), Emperor He ( AD) had Empress Dowager Dou (d. 97 AD) put under house arrest and her clan stripped of power. This was in revenge for Dou's purging of the clan of his natural mother—Consort Liang—and then concealing her identity from him. After Emperor He's death, his wife Empress Deng Sui (d. 121 AD) managed state affairs as the regent empress dowager during a turbulent financial crisis and widespread Qiang rebellion that lasted from 107 to 118 AD.

When Empress Dowager Deng died, Emperor An ( AD) was convinced by the accusations of the eunuchs Li Run and Jiang Jing (江京) that Deng and her family had planned to depose him. An dismissed Deng's clan members from office, exiled them and forced many to commit suicide. After An's death, his wife, Empress Dowager Yan (d. 126 AD) placed the child Marquess of Beixiang on the throne in an attempt to retain power within her family. However, palace eunuch Sun Cheng (d. 132 AD) masterminded a successful overthrow of her regime to enthrone Emperor Shun of Han ( AD). Yan was placed under house arrest, her relatives were either killed or exiled, and her eunuch allies were slaughtered. The regent Liang Ji (d. 159 AD), brother of Empress Liang Na (d. 150 AD), had the brother-in-law of Consort Deng Mengnü (later empress) (d. 165 AD) killed after Deng Mengnü resisted Liang Ji's attempts to control her. Afterward, Emperor Huan employed eunuchs to depose Liang Ji, who was then forced to commit suicide.

Students from the Imperial University organized a widespread student protest against the eunuchs of Emperor Huan's court. Huan further alienated the bureaucracy when he initiated grandiose construction projects and hosted thousands of concubines in his harem at a time of economic crisis. Palace eunuchs imprisoned the official Li Ying and his associates from the Imperial University on a dubious charge of treason. In 167 AD, the Grand Commandant Dou Wu (d. 168 AD) convinced his son-in-law, Emperor Huan, to release them. However the emperor permanently barred Li Ying and his associates from serving in office, marking the beginning of the Partisan Prohibitions.

Following Huan's death, Dou Wu and the Grand Tutor Chen Fan (d. 168 AD) attempted a coup d'état against the eunuchs Hou Lan (d. 172 AD), Cao Jie (d. 181 AD), and Wang Fu (王甫). When the plot was uncovered, the eunuchs arrested Empress Dowager Dou (d. 172 AD) and Chen Fan. General Zhang Huan favored the eunuchs. He and his troops confronted Dou Wu and his retainers at the palace gate where each side shouted accusations of treason against the other. When the retainers gradually deserted Dou Wu, he was forced to commit suicide.

Under Emperor Ling ( AD) the eunuchs had the partisan prohibitions renewed and expanded, while also auctioning off top government offices. Many affairs of state were entrusted to the eunuchs Zhao Zhong (d. 189 AD) and Zhang Rang (d. 189 AD) while Emperor Ling spent much of his time roleplaying with concubines and participating in military parades.

End of the Han dynasty

The Partisan Prohibitions were repealed during the Yellow Turban Rebellion and Five Pecks of Rice Rebellion in 184 AD, largely because the court did not want to continue to alienate a significant portion of the gentry class who might otherwise join the rebellions. The Yellow Turbans and Five-Pecks-of-Rice adherents belonged to two different hierarchical Daoist religious societies led by faith healers Zhang Jue (d. 184 AD) and Zhang Lu (d. 216 AD), respectively.

Zhang Lu's rebellion, in modern northern Sichuan and southern Shaanxi, was not quelled until 215 AD. Zhang Jue's massive rebellion across eight provinces was annihilated by Han forces within a year, however the following decades saw much smaller recurrent uprisings. Although the Yellow Turbans were defeated, many generals appointed during the crisis never disbanded their assembled militia forces and used these troops to amass power outside of the collapsing imperial authority.

General-in-Chief He Jin (d. 189 AD), half-brother to Empress He (d. 189 AD), plotted with Yuan Shao (d. 202 AD) to overthrow the eunuchs by having several generals march to the outskirts of the capital. There, in a written petition to Empress He, they demanded the eunuchs' execution. After a period of hesitation, Empress He consented. When the eunuchs discovered this, however, they had her brother He Miao (何苗) rescind the order. The eunuchs assassinated He Jin on September 22, 189 AD.

Yuan Shao then besieged Luoyang's Northern Palace while his brother Yuan Shu (d. 199 AD) besieged the Southern Palace. On September 25 both palaces were breached and approximately two thousand eunuchs were killed. Zhang Rang had previously fled with Emperor Shao ( AD) and his brother Liu Xie—the future Emperor Xian of Han ( AD). While being pursued by the Yuan brothers, Zhang committed suicide by jumping into the Yellow River.

General Dong Zhuo (d. 192 AD) found the young emperor and his brother wandering in the countryside. He escorted them safely back to the capital and was made Minister of Works, taking control of Luoyang and forcing Yuan Shao to flee. After Dong Zhuo demoted Emperor Shao and promoted his brother Liu Xie as Emperor Xian, Yuan Shao led a coalition of former officials and officers against Dong, who burned Luoyang to the ground and resettled the court at Chang'an in May 191 AD. Dong Zhuo later poisoned Emperor Shao.

Dong was killed by his adopted son Lü Bu (d. 198 AD) in a plot hatched by Wang Yun (d. 192 AD). Emperor Xian fled from Chang'an in 195 AD to the ruins of Luoyang. Xian was persuaded by Cao Cao (155–220 AD), then Governor of Yan Province in modern western Shandong and eastern Henan, to move the capital to Xuchang in 196 AD.

Yuan Shao challenged Cao Cao for control over the emperor. Yuan's power was greatly diminished after Cao defeated him at the Battle of Guandu in 200 AD. After Yuan died, Cao killed Yuan Shao's son Yuan Tan (173–205 AD), who had fought with his brothers over the family inheritance. His brothers Yuan Shang and Yuan Xi were killed in 207 AD by Gongsun Kang (d. 221 AD), who sent their heads to Cao Cao.

After Cao's defeat at the naval Battle of Red Cliffs in 208 AD, China was divided into three spheres of influence, with Cao Cao dominating the north, Sun Quan (182–252 AD) dominating the south, and Liu Bei (161–223 AD) dominating the west. Cao Cao died in March 220 AD. By December his son Cao Pi (187–226 AD) had Emperor Xian relinquish the throne to him and is known posthumously as Emperor Wen of Wei. This formally ended the Han dynasty and initiated an age of conflict between three states: Cao Wei, Eastern Wu, and Shu Han.

Culture and society

Social class

In the hierarchical social order, the emperor was at the apex of Han society and government. However the emperor was often a minor, ruled over by a regent such as the empress dowager or one of her male relatives. Ranked immediately below the emperor were the kings who were of the same Liu family clan. The rest of society, including nobles lower than kings and all commoners excluding slaves belonged to one of twenty ranks (ershi gongcheng 二十公乘).

Each successive rank gave its holder greater pensions and legal privileges. The highest rank, of full marquess, came with a state pension and a territorial fiefdom. Holders of the rank immediately below, that of ordinary marquess, received a pension, but had no territorial rule. Officials who served in government belonged to the wider commoner social class and were ranked just below nobles in social prestige. The highest government officials could be enfeoffed as marquesses.

By the Eastern Han period, local elites of unattached scholars, teachers, students, and government officials began to identify themselves as members of a larger, nationwide gentry class with shared values and a commitment to mainstream scholarship. When the government became noticeably corrupt in mid-to-late Eastern Han, many gentrymen even considered the cultivation of morally grounded personal relationships more important than serving in public office.

The farmer, or specifically the small landowner-cultivator, was ranked just below scholars and officials in the social hierarchy. Other agricultural cultivators were of a lower status, such as tenants, wage laborers, and slaves. The Han dynasty made adjustments to slavery in China and saw an increase in agricultural slaves. Artisans, technicians, tradespeople and craftsmen had a legal and socioeconomic status between that of owner-cultivator farmers and common merchants.

State-registered merchants, who were forced by law to wear white-colored clothes and pay high commercial taxes, were considered by the gentry as social parasites with a contemptible status. These were often petty shopkeepers of urban marketplaces; merchants such as industrialists and itinerant traders working between a network of cities could avoid registering as merchants and were often wealthier and more powerful than the vast majority of government officials.

Wealthy landowners, such as nobles and officials, often provided lodging for retainers who provided valuable work or duties, sometimes including fighting bandits or riding into battle. Unlike slaves, retainers could come and go from their master's home as they pleased. Medical physicians, pig breeders, and butchers had a fairly high social status, while occultist diviners, runners, and messengers had low status.

Marriage, gender, and kinship

The Han-era family was patrilineal and typically had four to five nuclear family members living in one household. Multiple generations of extended family members did not occupy the same house, unlike families of later dynasties. According to Confucian family norms, various family members were treated with different levels of respect and intimacy. For example, there were different accepted time frames for mourning the death of a father versus a paternal uncle.

Marriages were highly ritualized, particularly for the wealthy, and included many important steps. The giving of betrothal gifts, known as bridewealth and dowry, were especially important. A lack of either was considered dishonorable and the woman would have been seen not as a wife, but as a concubine. Arranged marriages were normal, with the father's input on his offspring's spouse being considered more important than the mother's.

Monogamous marriages were also normal, although nobles and high officials were wealthy enough to afford and support concubines as additional lovers. Under certain conditions dictated by custom, not law, both men and women were able to divorce their spouses and remarry. However, a woman who had been widowed continued to belong to her husband's family after his death. In order to remarry, the widow would have to be returned to her family in exchange for a ransom fee. Her children would not be allowed to go with her.

Apart from the passing of noble titles or ranks, inheritance practices did not involve primogeniture; each son received an equal share of the family property. Unlike the practice in later dynasties, the father usually sent his adult married sons away with their portions of the family fortune. Daughters received a portion of the family fortune through their marriage dowries, though this was usually much less than the shares of sons. A different distribution of the remainder could be specified in a will, but it is unclear how common this was.

Women were expected to obey the will of their father, then their husband, and then their adult son in old age. However, it is known from contemporary sources that there were many deviations to this rule, especially in regard to mothers over their sons, and empresses who ordered around and openly humiliated their fathers and brothers. Women were exempt from the annual corvée labor duties, but often engaged in a range of income-earning occupations aside from their domestic chores of cooking and cleaning.

The most common occupation for women was weaving clothes for the family, sale at market or for large textile enterprises that employed hundreds of women. Other women helped on their brothers' farms or became singers, dancers, sorceresses, respected medical physicians, and successful merchants who could afford their own silk clothes. Some women formed spinning collectives, aggregating the resources of several different families.

Education, literature, and philosophy

The early Western Han court simultaneously accepted the philosophical teachings of Legalism, Huang-Lao Daoism, and Confucianism in making state decisions and shaping government policy. However, the Han court under Emperor Wu gave Confucianism exclusive patronage. He abolished all academic chairs or erudites (bóshì 博士) not dealing with the Confucian Five Classics in 136 BCE and encouraged nominees for office to receive a Confucian-based education at the Imperial University that he established in 124 BCE.

Unlike the original ideology espoused by Confucius, or Kongzi (551–479 BCE), Han Confucianism in Emperor Wu's reign was the creation of Dong Zhongshu (179–104 BCE). Dong was a scholar and minor official who aggregated the ethical Confucian ideas of ritual, filial piety, and harmonious relationships with five phases and yin-yang cosmologies. Much to the interest of the ruler, Dong's synthesis justified the imperial system of government within the natural order of the universe.

The Imperial University grew in importance as the student body grew to over 30,000 by the 2nd century CE. A Confucian-based education was also made available at commandery-level schools and private schools opened in small towns, where teachers earned respectable incomes from tuition payments. Schools were established in far southern regions where standard Chinese texts were used to assimilate the local populace.

Some important texts were created and studied by scholars. Philosophical works written by Yang Xiong (53 BCE – 18 CE), Huan Tan (43 BCE – 28 CE), Wang Chong (27–100 CE), and Wang Fu (78–163 CE) questioned whether human nature was innately good or evil and posed challenges to Dong's universal order. The Records of the Grand Historian by Sima Tan (d. 110 BCE) and his son Sima Qian (145–86 BCE) established the standard model for all of imperial China's Standard Histories, such as the Book of Han written by Ban Biao (3–54 CE), his son Ban Gu (32–92 CE), and his daughter Ban Zhao (45–116 CE). There were dictionaries such as the Shuowen Jiezi by Xu Shen ( – CE) and the Fangyan by Yang Xiong.

Biographies on important figures were written by various gentrymen. Han dynasty poetry was dominated by the fu genre, which achieved its greatest prominence during the reign of Emperor Wu.

Law and order

Han scholars such as Jia Yi (201–169 BCE) portrayed the previous Qin dynasty as a brutal regime. However, archeological evidence from Zhangjiashan and Shuihudi reveal that many of the statutes in the Han law code compiled by Chancellor Xiao He (d. 193 BCE) were derived from Qin law.

Various cases for rape, physical abuse and murder were prosecuted in court. Women, although usually having fewer rights by custom, were allowed to level civil and criminal charges against men. While suspects were jailed, convicted criminals were never imprisoned. Instead, punishments were commonly monetary fines, periods of forced hard labor for convicts, and the penalty of death by beheading. Early Han punishments of torturous mutilation were borrowed from Qin law. A series of reforms abolished mutilation punishments with progressively less-severe beatings by the bastinado.

Acting as a judge in lawsuits was one of many duties of the county magistrate and Administrators of commanderies. Complex, high-profile or unresolved cases were often deferred to the Minister of Justice in the capital or even the emperor. In each Han county was several districts, each overseen by a chief of police. Order in the cities was maintained by government officers in the marketplaces and constables in the neighborhoods.

Food

The most common staple crops consumed during Han were wheat, barley, foxtail millet, proso millet, rice, and beans. Commonly eaten fruits and vegetables included chestnuts, pears, plums, peaches, melons, apricots, strawberries, red bayberries, jujubes, calabash, bamboo shoots, mustard plant, and taro. Domesticated animals that were also eaten included chickens, Mandarin ducks, geese, cows, sheep, pigs, camels, and dogs (various types were bred specifically for food, while most were used as pets). Turtles and fish were taken from streams and lakes. Commonly hunted game, such as owl, pheasant, magpie, sika deer, and Chinese bamboo partridge were consumed. Seasonings included sugar, honey, salt, and soy sauce. Beer and wine were regularly consumed.

Clothing

The types of clothing worn and the materials used during the Han period depended upon social class. Wealthy folk could afford silk robes, skirts, socks, and mittens, coats made of badger or fox fur, duck plumes, and slippers with inlaid leather, pearls, and silk lining. Peasants commonly wore clothes made of hemp, wool, and ferret skins.

Religion, cosmology, and metaphysics

Families throughout Han China made ritual sacrifices of animals and food to deities, spirits, and ancestors at temples and shrines. They believed that these items could be utilized by those in the spiritual realm. It was thought that each person had a two-part soul: the spirit-soul (hun 魂) which journeyed to the afterlife paradise of immortals (xian), and the body-soul (po 魄) which remained in its grave or tomb on earth and was only reunited with the spirit-soul through a ritual ceremony.

In addition to his many other roles, the emperor acted as the highest priest in the land who made sacrifices to Heaven, the main deities known as the Five Powers, and the spirits (shen 神) of mountains and rivers. It was believed that the three realms of Heaven, Earth, and Mankind were linked by natural cycles of yin and yang and the five phases. If the emperor did not behave according to proper ritual, ethics, and morals, he could disrupt the fine balance of these cosmological cycles and cause calamities such as earthquakes, floods, droughts, epidemics, and swarms of locusts.

It was believed that immortality could be achieved if one reached the lands of the Queen Mother of the West or Mount Penglai. Han-era Daoists assembled into small groups of hermits who attempted to achieve immortality through breathing exercises, sexual techniques and use of medical elixirs.

By the 2nd century CE, Daoists formed large hierarchical religious societies such as the Way of the Five Pecks of Rice. Its followers believed that the sage-philosopher Laozi was a holy prophet who would offer salvation and good health if his devout followers would confess their sins, ban the worship of unclean gods who accepted meat sacrifices and chant sections of the Daodejing.

Buddhism first entered Imperial China through the Silk Road during the Eastern Han, and was first mentioned in 65 CE. Liu Ying (d. 71 CE), a half-brother to Emperor Ming of Han ( CE), was one of its earliest Chinese adherents, although Chinese Buddhism at this point was heavily associated with Huang-Lao Daoism. China's first known Buddhist temple, the White Horse Temple, was constructed outside the wall of the capital, Luoyang, during Emperor Ming's reign. Important Buddhist canons were translated into Chinese during the 2nd century CE, including the Sutra of Forty-two Chapters, Perfection of Wisdom, Shurangama Sutra, and Pratyutpanna Sutra.

Government and politics

Central government

In Han government, the emperor was the supreme judge and lawgiver, the commander-in-chief of the armed forces and sole designator of official nominees appointed to the top posts in central and local administrations; those who earned a 600-bushel salary-rank or higher. Theoretically, there were no limits to his power.

However, state organs with competing interests and institutions such as the court conference (tíngyì 廷议)—where ministers were convened to reach majority consensus on an issue—pressured the emperor to accept the advice of his ministers on policy decisions. If the emperor rejected a court conference decision, he risked alienating his high ministers. Nevertheless, emperors sometimes did reject the majority opinion reached at court conferences.

Below the emperor were his cabinet members known as the Three Councillors of State (Sān gōng 三公). These were the Chancellor or Minister over the Masses (Chéngxiāng 丞相 or Dà sìtú 大司徒), the Imperial Counselor or Excellency of Works (Yùshǐ dàfū 御史大夫 or Dà sìkōng 大司空), and Grand Commandant or Grand Marshal (Tàiwèi 太尉 or Dà sīmǎ 大司马).

The Chancellor, whose title was changed to 'Minister over the Masses' in 8 BC, was chiefly responsible for drafting the government budget. The Chancellor's other duties included managing provincial registers for land and population, leading court conferences, acting as judge in lawsuits and recommending nominees for high office. He could appoint officials below the salary-rank of 600 bushels.

The Imperial Counselor's chief duty was to conduct disciplinary procedures for officials. He shared similar duties with the Chancellor, such as receiving annual provincial reports. However, when his title was changed to Minister of Works in 8 BC, his chief duty became oversight of public works projects.

The Grand Commandant, whose title was changed to Grand Marshal in 119 BC before reverting to Grand Commandant in 51 AD, was the irregularly posted commander of the military and then regent during the Western Han period. In the Eastern Han era he was chiefly a civil official who shared many of the same censorial powers as the other two Councillors of State.

Ranked below the Three Councillors of State were the Nine Ministers (Jiǔ qīng 九卿), who each headed a specialized ministry. The Minister of Ceremonies (Tàicháng 太常) was the chief official in charge of religious rites, rituals, prayers and the maintenance of ancestral temples and altars. The Minister of the Household (Guāng lù xūn 光禄勋) was in charge of the emperor's security within the palace grounds, external imperial parks and wherever the emperor made an outing by chariot.

The Minister of the Guards (Wèiwèi 卫尉) was responsible for securing and patrolling the walls, towers, and gates of the imperial palaces. The Minister Coachman (Tàipú 太仆) was responsible for the maintenance of imperial stables, horses, carriages and coach-houses for the emperor and his palace attendants, as well as the supply of horses for the armed forces. The Minister of Justice (Tíngwèi 廷尉) was the chief official in charge of upholding, administering, and interpreting the law. The Minister Herald (Dà hónglú 大鸿胪) was the chief official in charge of receiving honored guests at the imperial court, such as nobles and foreign ambassadors.

The Minister of the Imperial Clan (Zōngzhèng 宗正) oversaw the imperial court's interactions with the empire's nobility and extended imperial family, such as granting fiefs and titles. The Minister of Finance (Dà sìnóng 大司农) was the treasurer for the official bureaucracy and the armed forces who handled tax revenues and set standards for units of measurement. The Minister Steward (Shǎofǔ 少府) served the emperor exclusively, providing him with entertainment and amusements, proper food and clothing, medicine and physical care, valuables and equipment.

Local government

The Han empire, excluding kingdoms and marquessates, was divided, in descending order of size, into political units of provinces, commanderies, and counties. A county was divided into several districts (xiang 乡), the latter composed of a group of hamlets (li 里), each containing about a hundred families.

The heads of provinces, whose official title was changed from Inspector to Governor and vice versa several times during Han, were responsible for inspecting several commandery-level and kingdom-level administrations. On the basis of their reports, the officials in these local administrations would be promoted, demoted, dismissed or prosecuted by the imperial court.

A governor could take various actions without permission from the imperial court. The lower-ranked inspector had executive powers only during times of crisis, such as raising militias across the commanderies under his jurisdiction to suppress a rebellion.

A commandery consisted of a group of counties, and was headed by an Administrator. He was the top civil and military leader of the commandery and handled defense, lawsuits, seasonal instructions to farmers and recommendations of nominees for office sent annually to the capital in a quota system first established by Emperor Wu. The head of a large county of about 10,000 households was called a Prefect, while the heads of smaller counties were called Chiefs, and both could be referred to as Magistrates. A Magistrate maintained law and order in his county, registered the populace for taxation, mobilized commoners for annual corvée duties, repaired schools and supervised public works.

Kingdoms and marquessates

Kingdoms—roughly the size of commanderies—were ruled exclusively by the emperor's male relatives as semi-autonomous fiefdoms. Before 157 BC some kingdoms were ruled by non-relatives, granted to them in return for their services to Emperor Gaozu. The administration of each kingdom was very similar to that of the central government. Although the emperor appointed the Chancellor of each kingdom, kings appointed all the remaining civil officials in their fiefs.

However, in 145 BC, after several insurrections by the kings, Emperor Jing removed the kings' rights to appoint officials whose salaries were higher than 400 bushels. The Imperial Counselors and Nine Ministers (excluding the Minister Coachman) of every kingdom were abolished, although the Chancellor was still appointed by the central government.

With these reforms, kings were reduced to being nominal heads of their fiefs, gaining a personal income from only a portion of the taxes collected in their kingdom. Similarly, the officials in the administrative staff of a full marquess's fief were appointed by the central government. A marquess's Chancellor was ranked as the equivalent of a county Prefect. Like a king, the marquess collected a portion of the tax revenues in his fief as personal income.

Up until the reign of Emperor Jing of Han, the Emperors of the Han had great difficulty bringing the vassal kings under control, as kings often switched their allegiance to the Xiongnu Chanyu whenever threatened by Imperial attempts to centralize power. Within the seven years of Han Gaozu's reign, three vassal kings and one marquess either defected to or allied with the Xiongnu. Even imperial princes in control of fiefdoms would sometimes invite the Xiongnu to invade in response to threats by the Emperor to remove their power. The Han emperors moved to secure a treaty with the Chanyu to demarcate authority between them, recognizing each other as the "two masters" (两主), the sole representatives of their respective peoples, cemented with a marriage alliance (heqin), before eliminating the rebellious vassal kings in 154 BC. This prompted some vassal kings of the Xiongnu to switch their allegiance to the Han emperor from 147 BC. Han court officials were initially hostile to the idea of disrupting the status quo and expanding into the Xiongnu steppe territory. The surrendered Xiongnu were integrated into a parallel military and political structure under the Han Emperor, and opened the avenue for the Han dynasty to challenge the Xiongnu cavalry on the steppe. This also introduced the Han to the interstate networks in the Tarim Basin (Xinjiang), allowing for the expansion of the Han dynasty from a limited regional state to a universalist and cosmopolitan empire through further marriage alliances with another steppe power, the Wusun.

Military

At the beginning of the Han dynasty, every male commoner aged twenty-three was liable for conscription into the military. The minimum age for the military draft was reduced to twenty after Emperor Zhao's ( BC) reign. Conscripted soldiers underwent one year of training and one year of service as non-professional soldiers. The year of training was served in one of three branches of the armed forces: infantry, cavalry or navy. Soldiers who completed their term of service still needed to train to maintain their skill because they were subject to annual military readiness inspections and could be called up for future service - until this practice was discontinued after 30 AD with the abolishment of much of the conscription system. The year of active service was served either on the frontier, in a king's court or under the Minister of the Guards in the capital. A small professional (full time career) standing army was stationed near the capital.

During the Eastern Han, conscription could be avoided if one paid a commutable tax. The Eastern Han court favored the recruitment of a volunteer army. The volunteer army comprised the Southern Army (Nanjun 南军), while the standing army stationed in and near the capital was the Northern Army (Beijun 北军). Led by Colonels (Xiaowei 校尉), the Northern Army consisted of five regiments, each composed of several thousand soldiers. When central authority collapsed after 189 AD, wealthy landowners, members of the aristocracy/nobility, and regional military-governors relied upon their retainers to act as their own personal troops. The latter were known as 部曲, a special social class in Chinese history.

During times of war, the volunteer army was increased, and a much larger militia was raised across the country to supplement the Northern Army. In these circumstances, a General (Jiangjun 将军) led a division, which was divided into regiments led by Colonels and sometimes Majors (Sima 司马). Regiments were divided into companies and led by Captains. Platoons were the smallest units of soldiers.

Economy

Currency

The Han dynasty inherited the ban liang coin type from the Qin. In the beginning of the Han, Emperor Gaozu closed the government mint in favor of private minting of coins. This decision was reversed in 186 BC by his widow Grand Empress Dowager Lü Zhi (d. 180 BC), who abolished private minting. In 182 BC, Lü Zhi issued a bronze coin that was much lighter in weight than previous coins. This caused widespread inflation that was not reduced until 175 BC when Emperor Wen allowed private minters to manufacture coins that were precisely 2.6 g (0.09 oz) in weight.

In 144 BC Emperor Jing abolished private minting in favor of central-government and commandery-level minting; he also introduced a new coin. Emperor Wu introduced another in 120 BC, but a year later he abandoned the ban liangs entirely in favor of the wuzhu (五铢) coin, weighing 3.2 g (0.11 oz). The wuzhu became China's standard coin until the Tang dynasty (618–907 AD). Its use was interrupted briefly by several new currencies introduced during Wang Mang's regime until it was reinstated in 40 AD by Emperor Guangwu.

Since commandery-issued coins were often of inferior quality and lighter weight, the central government closed commandery mints and monopolized the issue of coinage in 113 BC. This central government issuance of coinage was overseen by the Superintendent of Waterways and Parks, this duty being transferred to the Minister of Finance during Eastern Han.

Taxation and property

Aside from the landowner's land tax paid in a portion of their crop yield, the poll tax and property taxes were paid in coin cash. The annual poll tax rate for adult men and women was 120 coins and 20 coins for minors. Merchants were required to pay a higher rate of 240 coins. The poll tax stimulated a money economy that necessitated the minting of over 28,000,000,000 coins from 118 BC to 5 AD, an average of 220,000,000 coins a year.

The widespread circulation of coin cash allowed successful merchants to invest money in land, empowering the very social class the government attempted to suppress through heavy commercial and property taxes. Emperor Wu even enacted laws which banned registered merchants from owning land, yet powerful merchants were able to avoid registration and own large tracts of land.

The small landowner-cultivators formed the majority of the Han tax base; this revenue was threatened during the latter half of Eastern Han when many peasants fell into debt and were forced to work as farming tenants for wealthy landlords. The Han government enacted reforms in order to keep small landowner-cultivators out of debt and on their own farms. These reforms included reducing taxes, temporary remissions of taxes, granting loans and providing landless peasants temporary lodging and work in agricultural colonies until they could recover from their debts.

In 168 BC, the land tax rate was reduced from one-fifteenth of a farming household's crop yield to one-thirtieth, and later to a one-hundredth of a crop yield for the last decades of the dynasty. The consequent loss of government revenue was compensated for by increasing property taxes.

The labor tax took the form of conscripted labor for one month per year, which was imposed upon male commoners aged fifteen to fifty-six. This could be avoided in Eastern Han with a commutable tax, since hired labor became more popular.

Private manufacture and government monopolies

In the early Western Han, a wealthy salt or iron industrialist, whether a semi-autonomous king or wealthy merchant, could boast funds that rivaled the imperial treasury and amass a peasant workforce of over a thousand. This kept many peasants away from their farms and denied the government a significant portion of its land tax revenue. To eliminate the influence of such private entrepreneurs, Emperor Wu nationalized the salt and iron industries in 117 BC and allowed many of the former industrialists to become officials administering the state monopolies. By Eastern Han times, the central government monopolies were repealed in favor of production by commandery and county administrations, as well as private businessmen.

Liquor was another profitable private industry nationalized by the central government in 98 BC. However, this was repealed in 81 BC and a property tax rate of two coins for every 0.2 L (0.05 gallons) was levied for those who traded it privately. By 110 BC Emperor Wu also interfered with the profitable trade in grain when he eliminated speculation by selling government-stored grain at a lower price than demanded by merchants. Apart from Emperor Ming's creation of a short-lived Office for Price Adjustment and Stabilization, which was abolished in 68 AD, central-government price control regulations were largely absent during the Eastern Han.

Science and technology

The Han dynasty was a unique period in the development of premodern Chinese science and technology, comparable to the level of scientific and technological growth during the Song dynasty (960–1279).

Writing materials

In the 1st millennium BC, typical ancient Chinese writing materials were bronzewares, animal bones, and bamboo slips or wooden boards. By the beginning of the Han dynasty, the chief writing materials were clay tablets, silk cloth, hemp paper, and rolled scrolls made from bamboo strips sewn together with hempen string; these were passed through drilled holes and secured with clay stamps.

The oldest known Chinese piece of hempen paper dates to the 2nd century BC. The standard papermaking process was invented by Cai Lun (AD 50–121) in 105. The oldest known surviving piece of paper with writing on it was found in the ruins of a Han watchtower that had been abandoned in AD 110, in Inner Mongolia.

Metallurgy and agriculture

Evidence suggests that blast furnaces, that convert raw iron ore into pig iron, which can be remelted in a cupola furnace to produce cast iron by means of a cold blast and hot blast, were operational in China by the late Spring and Autumn period (722–481 BC). The bloomery was nonexistent in ancient China; however, the Han-era Chinese produced wrought iron by injecting excess oxygen into a furnace and causing decarburization. Cast iron and pig iron could be converted into wrought iron and steel using a fining process.

The Han dynasty Chinese used bronze and iron to make a range of weapons, culinary tools, carpenters' tools and domestic wares. A significant product of these improved iron-smelting techniques was the manufacture of new agricultural tools. The three-legged iron seed drill, invented by the 2nd century BC, enabled farmers to carefully plant crops in rows instead of casting seeds out by hand. The heavy moldboard iron plow, also invented during the Han dynasty, required only one man to control it, two oxen to pull it. It had three plowshares, a seed box for the drills, a tool which turned down the soil and could sow roughly 45,730 m2 (11.3 acres) of land in a single day.

To protect crops from wind and drought, the grain intendant Zhao Guo (赵过) created the alternating fields system (daitianfa 代田法) during Emperor Wu's reign. This system switched the positions of furrows and ridges between growing seasons. Once experiments with this system yielded successful results, the government officially sponsored it and encouraged peasants to use it. Han farmers also used the pit field system ( 凹田) for growing crops, which involved heavily fertilized pits that did not require plows or oxen and could be placed on sloping terrain. In southern and small parts of central Han-era China, paddy fields were chiefly used to grow rice, while farmers along the Huai River used transplantation methods of rice production.

Structural and geotechnical engineering

Timber was the chief building material during the Han dynasty; it was used to build palace halls, multi-story residential towers and halls and single-story houses. Because wood decays rapidly, the only remaining evidence of Han wooden architecture is a collection of scattered ceramic roof tiles. The oldest surviving wooden halls in China date to the Tang dynasty (AD 618–907). Architectural historian Robert L. Thorp points out the scarcity of Han-era archeological remains, and claims that often unreliable Han-era literary and artistic sources are used by historians for clues about lost Han architecture.

Though Han wooden structures decayed, some Han-dynasty ruins made of brick, stone, and rammed earth remain intact. This includes stone pillar-gates, brick tomb chambers, rammed-earth city walls, rammed-earth and brick beacon towers, rammed-earth sections of the Great Wall, rammed-earth platforms where elevated halls once stood, and two rammed-earth castles in Gansu. The ruins of rammed-earth walls that once surrounded the capitals Chang'an and Luoyang still stand, along with their drainage systems of brick arches, ditches, and ceramic water pipes. Monumental stone pillar-gates, twenty-nine of which survive from the Han period, formed entrances of walled enclosures at shrine and tomb sites. These pillars feature artistic imitations of wooden and ceramic building components such as roof tiles, eaves, and balustrades.

The courtyard house is the most common type of home portrayed in Han artwork. Ceramic architectural models of buildings, like houses and towers, were found in Han tombs, perhaps to provide lodging for the dead in the afterlife. These provide valuable clues about lost wooden architecture. The artistic designs found on ceramic roof tiles of tower models are in some cases exact matches to Han roof tiles found at archeological sites.

Over ten Han-era underground tombs have been found, many of them featuring archways, vaulted chambers, and domed roofs. Underground vaults and domes did not require buttress supports since they were held in place by earthen pits. The use of brick vaults and domes in aboveground Han structures is unknown.

From Han literary sources, it is known that wooden-trestle beam bridges, arch bridges, simple suspension bridges, and floating pontoon bridges existed in Han China. However, there are only two known references to arch bridges in Han literature, and only a single Han relief sculpture in Sichuan depicts an arch bridge.

Underground mine shafts, some reaching depths over , were created for the extraction of metal ores. Borehole drilling and derricks were used to lift brine to iron pans where it was distilled into salt. The distillation furnaces were heated by natural gas funneled to the surface through bamboo pipelines. These boreholes perhaps reached a depth of 600 m (2000 ft).

File:登封汉代少室阙.jpg|A pair of stone-carved que (阙) located at the temple of Mount Song in Dengfeng. (Eastern Han dynasty.)

File:幽州书佐秦君石阙 17.jpg|A pair of Han period stone-carved que (阙) located at Babaoshan, Beijing.

File:Gao Yi Que2.jpg|A stone-carved pillar-gate, or que (阙), 6 m (20 ft) in total height, located at the tomb of Gao Yi in Ya'an. (Eastern Han dynasty.)

File:Eastern Han tomb, Luoyang 2.jpg|An Eastern-Han vaulted tomb chamber at Luoyang made of small bricks

Mechanical and hydraulic engineering

Han-era mechanical engineering comes largely from the choice observational writings of sometimes-disinterested Confucian scholars who generally considered scientific and engineering endeavors to be far beneath them. Professional artisan-engineers (jiang 匠) did not leave behind detailed records of their work. Han scholars, who often had little or no expertise in mechanical engineering, sometimes provided insufficient information on the various technologies they described. Nevertheless, some Han literary sources provide crucial information.

For example, in 15 BC the philosopher and poet Yang Xiong described the invention of the belt drive for a quilling machine, which was of great importance to early textile manufacturing. The inventions of mechanical engineer and craftsman Ding Huan are mentioned in the Miscellaneous Notes on the Western Capital. Around AD 180, Ding created a manually operated rotary fan used for air conditioning within palace buildings. Ding also used gimbals as pivotal supports for one of his incense burners and invented the world's first known zoetrope lamp.

Modern archeology has led to the discovery of Han artwork portraying inventions which were otherwise absent in Han literary sources. As observed in Han miniature tomb models, but not in literary sources, the crank handle was used to operate the fans of winnowing machines that separated grain from chaff. The odometer cart, invented during Han, measured journey lengths, using mechanical figures banging drums and gongs to indicate each distance traveled. This invention is depicted in Han artwork by the 2nd century, yet detailed written descriptions were not offered until the 3rd century.

Modern archeologists have also unearthed specimens of devices used during the Han dynasty, for example a pair of sliding metal calipers used by craftsmen for making minute measurements. These calipers contain inscriptions of the exact day and year they were manufactured. These tools are not mentioned in any Han literary sources.

The waterwheel appeared in Chinese records during the Han. As mentioned by Huan Tan about AD 20, they were used to turn gears that lifted iron trip hammers, and were used in pounding, threshing and polishing grain. However, there is no sufficient evidence for the watermill in China until about the 5th century. The Nanyang Commandery Administrator, mechanical engineer, and metallurgist Du Shi (d. 38 AD) created a waterwheel-powered reciprocator that worked the bellows for the smelting of iron. Waterwheels were also used to power chain pumps that lifted water to raised irrigation ditches. The chain pump was first mentioned in China by the philosopher Wang Chong in his 1st-century Balanced Discourse.

The armillary sphere, a three-dimensional representation of the movements in the celestial sphere, was invented in Han China by the 1st century BC. Using a water clock, waterwheel and a series of gears, the Court Astronomer Zhang Heng (AD 78–139) was able to mechanically rotate his metal-ringed armillary sphere. To address the problem of slowed timekeeping in the pressure head of the inflow water clock, Zhang was the first in China to install an additional tank between the reservoir and inflow vessel.

Zhang also invented a device he termed an "earthquake weathervane" ( 候风地动仪), which the British biochemist, sinologist, and historian Joseph Needham described as "the ancestor of all seismographs". This device was able to detect the exact cardinal or ordinal direction of earthquakes from hundreds of kilometers away. It employed an inverted pendulum that, when disturbed by ground tremors, would trigger a set of gears that dropped a metal ball from one of eight dragon mouths (representing all eight directions) into a metal toad's mouth.

The account of this device in the Book of the Later Han describes how, on one occasion, one of the metal balls was triggered without any of the observers feeling a disturbance. Several days later, a messenger arrived bearing news that an earthquake had struck in Longxi Commandery (in modern Gansu Province), the direction the device had indicated, which forced the officials at court to admit the efficacy of Zhang's device.

File:Winnowing machine and tilt hammer.JPG|A Han-dynasty pottery model of two men operating a winnowing machine with a crank handle and a tilt hammer used to pound grain.

File:EastHanSeismograph.JPG|A modern replica of Zhang Heng's seismometer

Mathematics

Three Han mathematical treatises still exist. These are the Book on Numbers and Computation, the Arithmetical Classic of the Gnomon and the Circular Paths of Heaven and the Nine Chapters on the Mathematical Art. Han-era mathematical achievements include solving problems with right-angle triangles, square roots, cube roots, and matrix methods, finding more accurate approximations for pi, providing mathematical proof of the Pythagorean theorem, use of the decimal fraction, Gaussian elimination to solve linear equations, and continued fractions to find the roots of equations.

One of the Han's greatest mathematical advancements was the world's first use of negative numbers. Negative numbers first appeared in the Nine Chapters on the Mathematical Art as black counting rods, where positive numbers were represented by red counting rods. Negative numbers were also used by the Greek mathematician Diophantus around AD 275, and in the 7th-century Bakhshali manuscript of Gandhara, South Asia, but were not widely accepted in Europe until the 16th century.

The Han applied mathematics to various diverse disciplines. In musical tuning, Jing Fang (78–37 BC) realized that 53 perfect fifths was approximate to 31 octaves while creating a musical scale of 60 tones, calculating the difference at 177147⁄176776 (the same value of 53 equal temperament discovered by the German mathematician Nicholas Mercator 1620–1687, i.e. 353/284).

Astronomy

Mathematics were essential in drafting the astronomical calendar, a lunisolar calendar that used the Sun and Moon as time-markers throughout the year. During the spring and autumn periods of the 5th century BC, the Chinese established the Sifen calendar (古四分历), which measured the tropical year at 365.25 days. This was replaced in 104 BC with the Taichu calendar (太初历) that measured the tropical year at (~ 365.25016) days and the lunar month at days. However, Emperor Zhang later reinstated the Sifen calendar.

Han Chinese astronomers made star catalogues and detailed records of comets that appeared in the night sky, including recording the 12 BC appearance of the comet now known as Halley's Comet.

Han dynasty astronomers adopted a geocentric model of the universe, theorizing that it was shaped like a sphere surrounding the earth in the center. They assumed that the Sun, Moon, and planets were spherical and not disc-shaped. They also thought that the illumination of the Moon and planets was caused by sunlight, that lunar eclipses occurred when the Earth obstructed sunlight falling onto the Moon, and that a solar eclipse occurred when the Moon obstructed sunlight from reaching the Earth. Although others disagreed with his model, Wang Chong accurately described the water cycle of the evaporation of water into clouds.

Cartography, ships, and vehicles

Evidence found in Chinese literature, and archeological evidence, show that cartography existed in China before the Han. Some of the earliest Han maps discovered were ink-penned silk maps found amongst the Mawangdui Silk Texts in a 2nd-century-BC tomb. The general Ma Yuan created the world's first known raised-relief map from rice in the 1st century. This date could be revised if the tomb of Emperor Qin Shi Huang is excavated and the account in the Records of the Grand Historian concerning a model map of the empire is proven to be true.

Although the use of the graduated scale and grid reference for maps was not thoroughly described until the published work of Pei Xiu (AD 224–271), there is evidence that in the early 2nd century, cartographer Zhang Heng was the first to use scales and grids for maps.

Han dynasty Chinese sailed in a variety of ships different from those of previous eras, such as the tower ship. The junk design was developed and realized during the Han era. Junk ships featured a square-ended bow and stern, a flat-bottomed hull or carvel-shaped hull with no keel or sternpost, and solid transverse bulkheads in the place of structural ribs found in Western vessels. Moreover, Han ships were the first in the world to be steered using a rudder at the stern, in contrast to the simpler steering oar used for riverine transport, allowing them to sail on the high seas.

Although ox-carts and chariots were previously used in China, the wheelbarrow was first used in Han China in the 1st century BC. Han artwork of horse-drawn chariots shows that the Warring-States-Era heavy wooden yoke placed around a horse's chest was replaced by the softer breast strap. Later, during the Northern Wei (386–534), the fully developed horse collar was invented.

File:Western Han Mawangdui Silk Map.JPG|An early Western Han dynasty silk map found in tomb 3 of Mawangdui, depicting the Kingdom of Changsha and Kingdom of Nanyue in southern China (note: the south direction is oriented at the top).

File:Eastern Han pottery boat.JPG|An Eastern Han dynasty pottery boat model with a steering rudder at the stern and anchor at the bow.

Medicine

Han-era medical physicians believed that the human body was subject to the same forces of nature that governed the greater universe, namely the cosmological cycles of yin and yang and the five phases. Each organ of the body was associated with a particular phase. Illness was viewed as a sign that qi or "vital energy" channels leading to a certain organ had been disrupted. Thus, Han-era physicians prescribed medicine that was believed to counteract this imbalance.

For example, since the wood phase was believed to promote the fire phase, medicinal ingredients associated with the wood phase could be used to heal an organ associated with the fire phase. Besides dieting, Han physicians also prescribed moxibustion, acupuncture, and calisthenics as methods of maintaining one's health. When surgery was performed by the Chinese physician Hua Tuo (d. AD 208), he used anesthesia to numb his patients' pain and prescribed a rubbing ointment that allegedly sped the process of healing surgical wounds. Whereas the physician Zhang Zhongjing ( – ) is known to have written the Shanghan lun ("Dissertation on Typhoid Fever"), it is thought that both he and Hua Tuo collaborated in compiling the Shennong Ben Cao Jing medical text.