Edward Porter Alexander, Military memoirs of a Confederate: a critical narrative

When Lee learned of the absence of the cavalry, he at first proposed to defer the attack only a single day. Jackson is said to have urged that it would be best to make no delay at all, but to go ahead with the infantry. But the reports from the signal station on Clark's Mountain represented the enemy as quiet, and Lee decided to wait. Later, a telegraphic despatch from Fitzhugh Lee representing his animals as in bad condition, it was decided to postpone the movement until the 20th, and orders were issued accordingly.

Doubtless, Lee found it hard to believe that Pope, so soon after his boasting order, and still sooner after the ‘victory’ he had claimed at Cedar Mountain, would now turn his back and fly without firing a shot; but, later on that day, there came reports of activity and stir among the enemy's camps, and on the 19th Lee and Longstreet, going up the mountain to see for themselves, saw Pope's whole army march away to the Rappahannock.

On the 20th Lee's advance took place, but although the march was rapidly made in hopes of overtaking some delayed portion of the enemy, the hopes proved vain.

On the north side of the Rappahannock, Pope found such advantages of position that, although for five precious days Lee sought diligently by feints and demonstrations to find a favorable opening, his efforts were vain. But to do nothing was to lose the campaign. By a bold raid of Stuart's, however, Lee now had the good luck to turn the tables and come into possession of Pope's private despatch book, with copies of his most important correspondence with Lincoln, Halleck, and others. Stuart had gotten Lee's permission to try to burn a railroad bridge over Cedar Run, near Catlett's Station, some 12 miles in rear of Pope's army. With about 1500 cavalry and two guns, he crossed the Rappahannock at Waterloo Bridge, above Pope's right flank, on Aug. 22, and pushed on through Warrenton toward Catlett's Station. A terrific rain-storm came on late in the afternoon, and in it the command captured the enemy's picket and surprised the Federal encampments. The night was memorable for black darkness, the time being just at the change of the moon. A negro recognized Stuart and volunteered to lead him to the camp of Pope's staff and baggage. A regiment under W. H. F. Lee raided this