Titus Livius (Livy), The History of Rome, Book 27
Cyrus Evans, Ed.

28. Hannibal, concluding that the enemy were greatly dismayed by one of their consuls being slain and the other wounded, that he might not be wanting on any opportunity presenting itself, immediately transferred his camp to the eminence on which the battle had been fought. [2] Here he found the body of Marcellus, and interred it. Crispinus, disheartened by the death of his colleague and his own wound, set out during the silence of the following night, and encamped upon the nearest mountains he could reach, in a position elevated and secured on all sides. [3] Here the two generals exerted their sagacity, the one in effecting, the other in guarding against, a deception. Hannibal got possession of the ring of Marcellus, together with his body. [4] Crispinus, fearing lest any artifice should be practised by the Carthaginian's employing this signet as the means of deception, had sent round messengers to the neighbouring states, informing them, that “his colleague had been slain, and that the enemy were in possession of his seal, and that they must not give credit to any letters written in the name of Marcellus.” [5] This message of the consul arrived at Salapia a little before a letter was brought from Hannibal, written in the name of Marcellus, to the effect, that “he should come to Salapia on the night which followed that day; that the soldiers in the garrison should hold themselves in readiness, in case he might want to employ them on any service.” [6] The Salapians were aware of the fraud, and concluding that an opportunity for punishing them was sought by Hannibal, from resentment, not only on account of their defection, but also because they slew his [7??] horsemen, sent his messenger, who was a deserter from the Romans, back again, in order that the soldiers might do what was thought necessary, without his being privy to it, and then placed the townsmen in parties to keep guard along the walls, and in convenient parts of the city. [8] The guards and watches they formed with extraordinary care for that night, and on each side of the gate at which they supposed the enemy would come, they opposed to them the choicest of the troops in the garrison. [9] About the fourth watch, Hannibal approached the city. His vanguard was composed of Roman deserters, with [p. 1131]Roman arms. These, all of whom spoke the Latin language, when they reached the gate, called up the guards, and ordered the gate to be opened, for the consul had arrived. [10] The guards, as if awakened at their call, began to be in a hurry and bustle, and exert themselves in opening the gate, which was closed by letting down the portcullis; some raised this with levers, others drew it up with ropes to such a height that the men could come in without stooping. [11] The opening was scarcely wide enough, when the deserters eagerly rushed through the gate, and after about six hundred had got in, the rope being let go by which it was suspended, the portcullis fell with a loud noise. [12] Some of the Salapians fell upon the deserters, who were carrying their arms carelessly suspended upon their shoulders, as is customary after a march, as if among friends; others frightened away the enemy by discharging stones, pikes, and javelins from the tower adjoining the gate and from the walls. [13] Thus Hannibal withdrew, having been caught by his own stratagem, and proceeded to raise the siege of Locri, which Cincius was carrying on with the greatest vigour, with works and engines of every kind, which were brought from Sicily. [14] Mago, who by that time almost despaired of retaining and defending the town, derived his first gleam of hope on the death of Marcellus being reported. [15] This was followed by a message, that Hannibal had despatched his Numidian cavalry in advance, and was himself following them with all possible speed with a body of infantry. [16] As soon, therefore, as he was informed, by a signal displayed from the watch-towers, that the Numidians were drawing near, suddenly throwing open the gate he sallied out boldly upon the enemy, and at first, more because he had done it unexpectedly than from the equality of his strength, the contest was doubtful; [17] but afterwards, when the Numidians came up, the Romans were so dismayed that they fled on all hands to the sea and their ships, leaving their works and the engines with which they battered the walls. Thus the siege of Locri was raised by the approach of Hannibal.