Jeb Stuart’s cavalry screened the Confederate infantry as it marched north behind the sheltering Blue Ridge Mountains. On June 17, 1863, Pleasanton sent forward the 1st Rhode Island Cavalry under the command of Col. Alfred Duffié to Middelburg. Unsupported, Duffié's regiment pushed aside Rebel skirmishers and entered town, but was then overpowered there by the brigade of Brig. Gen. Beverly Robertson. The 1st Rhode Island was routed, taking about 225 casualties. On June 19, Stuart pulled back toward the Blue Ridge. The brigade of Col. J. Irvin Gregg’s advanced, driving Robertson’s cavalry to high ground one mile beyond Middleburg. Both sides were reinforced and mounted and dismounted skirmishing continued. The Yankee troopers forced Stuart's men out of their position but the Rebel cavalry fell back again toward Upperville, still covering the approaches to the Blue Ridge. The battles at Aldie, Middleburg and Upperville along the Ashby's Gap Turnpike successfully delayed the Union cavalry thrust across the Loudoun Valley, preventing them from finding Lee's army.