Major engagements between the regular armies also occurred in the Valley, particularly in 1862 and 1863. In November 1862, following the Battle of Antietam, Union Gen. George McClellan marched his army through the Valley in slow pursuit of the retreating Army of Northern Virginia. Confederate cavalry under Maj. Gen. J.E.B. Stuart fought a delaying action against the vanguard of the Union columns during the often overlooked Battle of Unison. During the Gettysburg Campaign, a series of cavalry clashes between J.E.B. Stuart and Alfred Pleasonton occurred in the valley at Aldie, Middleburg, Goose Creek, and Upperville. Stuart successfully kept the Federal forces from entering the adjacent Shenandoah Valley and discovering Robert E. Lee's main army. In 1864, as General Jubal Early withdrew from Washington, Union forces attacked his supply wagons at Heaton's Crossroads at present-day Purcellville. In the early winter of 1864, General Phillip Sheridan had the Loudoun Valley put to the torch during The Burning Raid in response to actions of Confederate partisans John Mosby who used the Loudoun Valley as his base of operations.