The Seven Days Battles began with a Union attack in the minor Battle of Oak Grove on June 25, 1862, but Union Maj. Gen. George B. McClellan and his Army of the Potomac quickly lost the initiative as Confederate General Robert E. Lee and his Army of Northern Virginia began a series of attacks at Beaver Dam Creek on June 26, Gaines' Mill on June 27, and the minor actions at Garnett's and Golding's Farm on June 27 and June 28. The Army of the Potomac continued its retreat toward the James River.