Prior to Gettysburg, Robert E. Lee had established a reputation as an almost invincible general, achieving stunning victories against superior numbers—although usually at the cost of high casualties to his army—during the Seven Days, the Northern Virginia Campaign (including the Second Battle of Bull Run), Fredericksburg, and Chancellorsville. Only the Maryland Campaign, with its tactically inconclusive Battle of Antietam, had been less than successful. Therefore, historians have attempted to explain how Lee's winning streak was interrupted so dramatically at Gettysburg. Although the issue is tainted by attempts to portray history and Lee's reputation in a manner supporting different partisan goals, the major factors in Lee's loss arguably can be attributed to: (1) his overconfidence in the invincibility of his men; (2) the performance of his subordinates, and his management thereof; (3) his failing health, and (4) the performance of his opponent, George G. Meade, and the Army of the Potomac.