the Shenandoah; intrench another brigade at Strasburg; build and occupy blockhouses at the railway bridges; leave two regiments of cavalry at Winchester, and keep his front covered by constantly employed cavalry well advanced—the general object being to cover the line of the Potomac and Washington, and, he doubtless mentally added, protect the right of the army moving toward Fredericksburg.
Banks hastened to comply with these orders.
Shields' division was recalled from Strasburg, and on the 20th, Williams' division took up its line of march for Manassas.
Ashby, who kept up a constant skirmish with the Federal advance between Woodstock and Strasburg, routing its pickets and peering into its camps, reported to Jackson on the evening of March 21st, that the enemy had evacuated Strasburg and he was following them.
Jackson, having been instructed by Johnston to hold in the valley the enemy already there, followed after Ashby at dawn of the 22d, Fulkerson's brigade from Woodstock and G