Battle of Chancellorville

General Ambrose Burnside was replaced with Joseph Hooker. Hooker immediately set out to reorganize the Army of the Potomac, a task at which he succeeded. In the end of April 1863, he launched his attack on Confederate forces. One part of his army crossed the Rappahannock south of Fredericksburg, the other crossed the river 12 miles to the north. Hooker successfully outflanked Lee. However, when Hooker's forces encountered their first serious opposition, he ordered an end to the advance and a partial withdrawal. This allowed Lee to organize for the attack, and in a flanking maneuver, he rolled back the Union line. Hooker was forced to withdraw from the South side of the Rappahannock– both in the North and in the South, where Sedgwick's corps had captured the Marye Heights. The Confederates, however, lost Stonewall Jackson, a victim of friendly fire.