It was John Buford's cavalry division which touched off the Battle of Gettysburg itself, engaging the Confederate division of Henry Heth to prevent him from occupying Gettysburg on July 1. Buford's troopers played a major part in slowing Heth's initial advance, and, after being relieved by infantry, spent the rest of July 1 screening and scouting. His division was sent to guard the army's supply trains for the remainder of the battle, but the divisions of Gregg and Kilpatrick remained on the field. On July 3, concurrent with Pickett's Charge, Gregg's division (with Custer's brigade of Kilpatrick's division) engaged Stuart east of Gettysburg and checked repeated Confederate advances. However, on the same day south of Gettysburg, Kilpatrick ordered a futile charge by the brigade of Elon J. Farnsworth against Confederate positions on Big Round Top, resulting in Farnsworth's death and heavy casualties among his men.