Answer:
Gen. Robert E. Lee's downfall by the Army of the Potomac pushed his Confederate troops to withdraw; they nevermore retrieved.
Step-by-step explanation:
Lee was encouraged by his triumph in Chancellorsville, in May 1863 and expected to harden his seeming support in Gettysburg. He was unaware for the brutality and energy of the Union armies beneath the lately called Potomac Army commandant, Gen. George G. Meade.