After the early summer collapse of the Union Peninsula Campaign offensive to capture Richmond, Robert E. Lee sought to move his army north and threaten Washington DC before Union forces could regroup. His trusted and highly capable "wing" commanders, Maj. Gen. "Stonewall" Jackson and Lieut. Gen. James Longstreet, brought Lee's army within 35 miles of the Union capital by the end of August. Jackson waited for the arriving Union army near Manassas. Longstreet, trailing Jackson by a day, met the Union division of Brig. Gen. James Ricketts at Thoroughfare Gap in the Bull Run Mountains on August 28th. Georgia regiments from two brigades fought the defending Yankees from Pennsylvania and Massachusetts on the steep north and south slopes of the gap near Chapman's Mill along both sides of the Manassas Gap Railroad. Defeated by the end of the day, and flanked by a three brigades under Brig. Gen. Cadmus Wilcox passing through Hopewell Gap several miles to the north, Ricketts retired, withdrawing east via Gainesville to Manassas Junction. The seemingly inconsequential battle fought here virtually ensured Maj. Gen. John Pope’s defeat during the battle at Manassas on Aug. 29-30th because it allowed the two wings of Lee’s army to unite against him.