Background:
* After defeating the Union Army at the First Battle of Bull Run in July 1861, the Confederate army under General Robert E. Lee took up defensive positions south of the Rappahannock River in Virginia.
* In the spring of 1862, the Union army under General George B. McClellan launched the Peninsula Campaign, an attempt to capture the Confederate capital of Richmond, Virginia.
* McClellan's campaign stalled, and Lee took the opportunity to launch a counteroffensive. He divided his army and sent one wing under General Thomas J. "Stonewall" Jackson to the Shenandoah Valley, while he took the other wing to attack McClellan's army.
The Battle:
* Jackson's wing of the Confederate army defeated the Union forces at the Battle of Front Royal on May 23, 1862, and the Battle of Winchester on May 25.
* This forced McClellan to withdraw his army from the Peninsula and move north to defend Washington, D.C.
* Lee then combined his two wings and marched north to meet McClellan's army.
* The two armies clashed at Second Bull Run on August 28-30, 1862.
* The first day of the battle was inconclusive, with both sides suffering heavy casualties.
* On the second day, Lee launched a massive assault on the Union right flank.
* The Union line collapsed, and the Union army was forced to retreat in disorder.
Aftermath:
* The Confederate victory at Second Bull Run boosted morale and gave the Confederacy a much-needed psychological boost.
* It also led to the resignation of McClellan as commander of the Union army.
* The battle marked a turning point in the war, as the Confederacy began to take the initiative and win more battles.