 Complete the following phrase:  Marching two days later across the former battlefield of Bull Run, his regiment clashed again with Confederates  this time at Aldie on June 22. Assigned to guard the rear of the Union Army as it marched for Pennsylvania, the 1st Pennsylvania Cavalrymen reached the battlefield at Gettysburg during the morning of July 2, and were immediately assigned to duties at the headquarters of General George Meade for the remainder of the engagement before guarding the Unions reserve artillery as it made its way back from Pennsylvania into Maryland beginning July 5, 1863. Rejoining their brigade by mid-month, they next engaged the enemy near Shepardstown before withdrawing to Bolivar Heights. Encamped near Warrenton beginning July 27, they were assigned to guard, picket and scouting duties through mid-September when they joined other Union forces in re-engaging intensely with the enemy for three hours from Muddy Run to Culpepper on September 13, after which the 1st Pennsylvanians were sent out on skirmish assignments. Their next major engagements came in the Bristoe Campaign from October through November 1863, including the 