When McDowell advanced upon the Confederate forces under Beauregard at Manassas, Johnston moved from the Shenandoah Valley with great rapidity to Beauregard's assistance.
On the 14th of May 1861 he was appointed colonel of the 13th U.S. Infantry, a new regiment, and was soon assigned to command a brigade in General McDowell's army in front of Washington.
On the 21st of July took place the first battle of Bull Run (q.v.) between McDowell and Beauregard, fought by the raw troops of both sides with an obstinacy that foreboded the desperate battles of subsequent campaigns.
It was eventually decided that General Banks was to oppose "Stonewall" Jackson in the Shenandoah Valley, Fremont to hold western Virginia against the same general's enterprise, and McDowell with a strong corps to advance overland to meet McClellan, who, with the main army, was to proceed by sea to Fortress Monroe and thence to advance on Richmond.
Banks's main army, early in May, lay far down the Valley at Strasburg and Front Royal, Fremont at the town of McDowell.
