After Confederate Gen. Robert E. Lee's victory at Chancellorsville in May 1863, he led the Army of Northern Virginia into the Shenandoah Valley, then north through Maryland and across the Mason-Dixon Line into Pennsylvania, while Union Gen. George G. Meade, who replaced Gen. Joseph Hooker on June 28, led the Army of the Potomac in pursuit. On the afternoon of June 21, 1863, two Northern and Southern cavalry brigades totaling about 6,000 men, with horse artillery supporting both sides, clashed across the Ayrshire and Kirkby farms as part of the Battle of Upperville. Confederate Gen. J.E.B. Stuart's cavalry division blocked Federal horsemen who were trying to locate Lee's army as it marched into the Shenandoah Valley. Three miles to the southeast, Stuart fought to hold Vineyard Hill east of Upperville long enough for Gen. William E. Jones's and Col. John R. Chambliss's brigades to pass through the road junction of Trappe Road and Ashby's Gap Turnpike. As those Confederate brigades fought in these fields and raced south, Union Gen. John Buford, with Col. William Gamble's and Col. Thomas C. Devin's brigades, charged from the east. The Confederate defense stopped the Federal attack and allowed Jones, Chambliss, and their men to withdraw to Ashby's Gap near Paris in the Blue Ridge Mountains, leaving Lee's army safe in the Valley. The opposing armies later collided at Gettysburg on July 1, and ten days after the Trappe Road Fight, Buford reached the high point of his career by holding the ridges west of Gettysburg until Union infantry arrived; less than six months later, he died of typhus in Washington, D.C.