It was thus necessary to act with decision, and General Lee resolved upon a movement apparently of the most reckless character. This was to separate his army into two parts, and, while one remained confronting the enemy on the Rappahannock, send the other by a long circuit to fall on the Federal rear near Manassas. This plan of action was opposed to the first rule of the military art, that a general should never divide his force in the face of an enemy. That Lee ventured to do so on this occasion can only be explained on one hypothesis, that he did not highly esteem the military ability of his opponent. These flank attacks undoubtedly, however, possessed a great attraction for him, as they did for Jackson, and, in preferring such movement, Lee was probably actuated both by the character of the troops on both sides and by the nature of the country. The men of both armies were comparatively raw levies, highly susceptible to the influence of "surprise," and the appearance of an enemy on their flanks, or in their rear, was calculated to throw them into disorder. The wooded character of the theatre of war generally rendered such movements practicable, and all that was requisite was a certain amount of daring in the commander who was called upon to decide upon them. This daring Lee repeatedly exhibited, and the uniform success of the movements indicates his sound generalship.

To command the force which was now to go on the perilous errand of striking General Pope's rear, General Lee selected Jackson, who had exhibited such promptness and decision in the campaigns of the Valley of Virginia. Rapidity of movement was necessary above all things, and, if any one could be relied upon for that, it was the now famous Stonewall Jackson. To him the operation was accordingly intrusted, and his corps was at once put in motion. Crossing the Rappahannock at an almost forgotten ford, high up and out of view of the Federal right, Jackson pushed forward day and night toward Manassas, reached Thoroughfare Gap, in the Bull Run Mountain, west of that place, passed through, and completely destroyed the great mass of supplies in the Federal depot at Manassas. The whole movement had been made with such rapidity, and General Stuart, commanding the cavalry, had so thoroughly guarded the flank of the advancing column from observation, that Manassas was a mass of smoking ruins almost before General Pope was aware of the real danger. Intelligence soon reached him, however, of the magnitude of the blow aimed by Lee, and, hastily breaking up his camps on the Rappahannock, he hurried to attack the force assailing his communications.

The first part of General Lee's plan had thus fully succeeded. General Pope, who had occupied every ford of the Rappahannock, so as to render the passage difficult, if not impossible, had disappeared suddenly, to go and attack the enemy in his rear. General Lee promptly moved in his turn, with the great corps under Longstreet, and pushed toward Manassas, over nearly the same road followed by Jackson.

[Illustration: T.J. Jackson]