At dawn June 9, the Union cavalry corps under Maj. Gen. Alfred Pleasonton launched a surprise attack on Stuart's cavalry at Brandy Station. After an all-day fight in which fortunes changed repeatedly, the Federals retired without discovering Lee's infantry camped near Culpeper. This battle marked the apogee of the Confederate cavalry in the East. From this point in the war, the Federal cavalry gained strength and confidence. Brandy Station was the largest cavalry battle of the war and the opening engagement of the Gettysburg Campaign.