The retirement of Jackson, and the unopposed occupation of the lower Valley by Banks, relieved General McClellan of all fears in that direction, and induced him, in pursuance of President Lincoln's requirement that Manassas Junction and the approaches to, Washington from that direction be securely held, to send the following instructions to Banks on March 16th:
Sir — You will post your command in the vicinity of Manassas, entrench yourself strongly, and throw cavalry pickets out to the front.
Your first care will be the rebuilding of the railway from Washton to Manassas, and to Strasburg, in order to open your communications to the Valley of the Shenandoah. As soon as the Manassas Gap railway is in running order, entrench a brigade of infantry, say four regiments, with two batteries, at or near the point where the railway crosses the Shenandoah. Something like two regiments of cavalry should be left in that vicinity to occupy Winchester, and thoroughly scour the country south of the railway and up the Shenandoah Valley. * * * Occupy by grand guards Warrenton Junction and Warrenton itself, and some * * more advanced point on the Orange and Alexandria railroad.
--McClellan's report.
In compliance with these instructions, Shields' division was recalled from Strasburg, and Williams' division began its movement toward Manassas on the 20th of March.
On the evening of the 21st Ashby reported that the enemy had evacuated Strasburg. Jackson, divining that this meant a withdrawal toward Washington, at once ordered pursuit with all his. available force. The whole of his little army reached Strasburg