The First Battle of Bull Run, also known as First Manassas, was fought on July 21, 1861, in Prince William County, Virginia, near the city of Manassas. It was the first major land battle of the American Civil War. Just months after the start of the war at Fort Sumter, the Northern public clamored for a march against the Confederate capital of Richmond, Virginia, which they expected to bring an early end to the rebellion. Yielding to political pressure, Brig. Gen. Irvin McDowell led his unseasoned Union Army across Bull Run against the equally inexperienced Confederate Army of Brig. Gen. P. G. T. Beauregard camped near Manassas Junction. McDowell's ambitious plan for a surprise flank attack on the Confederate left was poorly executed by his officers and men; nevertheless, the Confederates, who had been planning to attack the Union left flank, found themselves at an initial disadvantage. Confederate reinforcements under Brig. Gen. Joseph E. Johnston arrived from the Shenandoah Valley by railroad and the course of the battle quickly changed. A brigade of Virginians under the relatively unknown brigadier general from the Virginia Military Institute, Thomas J. Jackson, stood their ground and Jackson received his famous nickname, "Stonewall Jackson". The Confederates launched a strong counterattack, and as the Union troops began withdrawing under fire, many panicked and the retreat turned into a rout. McDowell's men frantically ran without order in the direction of Washington, D.C. Both armies were sobered by the fierce fighting and many casualties, and realized the war was going to be much longer and bloodier than either had anticipated.