One of the most dramatic battles of the Civil War, Chancellorsville was Robert E. Lee's masterpiece. Outnumbered two to one, Lee violated a cardinal rule of military strategy by dividing his small army, sending Stonewall Jackson on his famous twelve-mile march around the Union flank. Charging out of the Wilderness with Rebel yells, Jackson's troops destroyed one entire corps of the Union army, and Lee drove the rest across the Rappahannock River. Lee's great victory came at great cost, however: Jackson, making a night reconnaissance, was accidentally shot by his own troops and died eight days later. And ironically, the momentum of Lee's greatest triumph pushed him to launch an aggressive campaign that led to his greatest defeat, at Gettysburg.