of General Irvin McDowell. With great fanfare, these untrained soldiers set out from Washington DC with the idea that they would capture Richmond in six weeks and put a quick end to the conflict. At the Battle of Bull Run on July 21, however, disaster ensued as McDowell's army was completely routed and fled back to the nation's capitol. Major General George McClellan of the Union was put in command of the Army of the Potomac following the battle on July 26, 1861. He began to reconstruct the shattered army and turn it into a real fighting force, as it became clear that there would be no quick, six-week resolution of the conflict. Despite pressure from the White House, McClellan did not move until March 1862, when the Peninsular Campaign began with the purpose of capturing the capitol of the Confederacy, Richmond, Virginia. It was initially successful, but in the final days of the campaign, McClellan faced strong opposition from Robert E. Lee, the new commander of the Army of Northern Virginia. From June 25 to July 1, in a series of battles known as the Seven Days Battles, Lee forced the Army of the Potomac to retreat. McClellan was recalled to Washington and a new army assembled under the command of John Pope. In August, Lee fought the Second Battle of Bull Run (Second Manassas) and defeated John Pope's Army of Virginia. Pope was dismissed from command and his army merged with McClellan's. The Confederates then invaded Maryland, hoping to obtain European recognition and an end to the war. The two armies met at Antietam on September 17. This was the single bloodiest day in American history. The Union victory allowed Abraham Lincoln to issue the Emancipation Proclamation, which declared that all slaves in states still in rebellion as of January 1, 1863 were freed. This did not actually end slavery, but it served to give a meaningful cause to the war and prevented any possibility of European intervention. Militarily, the Union could not follow up its victory at Antietam. McClellan failed to pursue the Confederate army, and President Lincoln finally became tired of his excuses and unwillingness to fight. He was dismissed from command in October and replaced by Ambrose Burnside, despite his pleas that he was not ready for the job. He attempted to invade Richmond from the north (McClellan had tried from the east), but the