Hancock's only significant military defeat occurred during the siege of Petersburg. His II Corps moved south of the city, along the Wilmington and Weldon Railroad, tearing up track. On August 25, Confederate Maj. Gen. Henry Heth attacked and overran the faulty Union position at Reams's Station, shattering the II Corps, capturing many prisoners. Despite a later victory at Hatcher's Run, the humiliation of Reams's Station contributed, along with the lingering effects of his Gettysburg wound, to his decision to give up field command in November. He left the II Corps after a year in which it had suffered over 40,000 casualties, but had achieved significant military victories. His next assignment was to command the ceremonial First Veteran Corps. He performed more recruiting, commanded the Middle Department, and relieved Maj. Gen. Philip Sheridan in command of forces in the now-quiet Shenandoah Valley. He was promoted to brevet major general in the regular army for his service at Spotsylvania, effective March 13, 1865.