In the final days of August 1862, Gen. Lee scourged Union forces, routing them at Manassas Junction in the Second Battle of Bull Run, this time, against Maj. Gen. Pope and his Army of Virginia. A number of people, including Maj. Gen. Halleck and Secretary Stanton, thought Lee would turn his attention to Washington. Instead, Lee began the Maryland Campaign. The campaign started with a skirmish at Mile Hill on September 4, followed by a major confrontation at Harpers Ferry. Lincoln, without consulting Stanton, perhaps knowing Stanton would object, merged Pope's Army of Virginia into McClellan's Army of the Potomac. With 90,000 men, McClellan launched his army into the bloody Battle of Antietam, and emerged victorious, pushing the Army of Northern Virginia back into Virginia, and effectively ending Lee's Maryland offensive. McClellan's success at Antietam Creek emboldened him to demand that Lincoln and his government cease obstructing his plans, Halleck and Stanton be removed, and he be made general-in-chief of the Union Army. Meanwhile, he refused to move aggressively against Lee and the Army of Northern Virginia, which was withdrawing towards Richmond. McClellan's unreasonable requests continued, as did his indolence, and Lincoln's patience with him soon grew thin. Lincoln dismissed him from leadership of the Army of the Potomac on November 5. Maj. Gen. Ambrose Burnside replaced McClellan days later.