George B. McClellan was a major general in the Union army during the American Civil War (1861–1865). Styled the "Young Napoleon" by the press, his battlefield successes and failures were eclipsed by controversies that arose between him and his superiors, especially U.S. president Abraham Lincoln. Following the Union debacle at the First Battle of Manassas in July 1861, McClellan formed and took command of the Army of the Potomac, expertly training it and earning the love and devotion of his men. He led the army first through the unsuccessful Peninsula Campaign and the Seven Days' Battles outside Richmond in 1862, and then through the climactic Battle of Antietam on September 17, 1862, which forced Confederate general Robert E. Lee to abandon his invasion of the North. Lincoln, however, was dissatisfied with McClellan's lack of aggression and relieved him of command. McClellan, a Democrat, responded by challenging the Republican president in the 1864 election. It was both the logical culmination of his advocacy for a limited-war strategy, and perhaps the clumsiest confirmation of his critics' accusations that his military caution was politically motivated. After McClellan lost his run for the presidency, he retired first to Europe and then to New Jersey, where he became governor.