After Fredericksburg, Hooker replaced Burnside in command of the Union Army of the Potomac. He developed a sound plan to divide his forces, leaving part of a corps in Fredericksburg to look like they were staying put, then sending Sedgewick with a third of his men east to demonstrate against the Confederate right flank while he took the rest of his men north and west to crush their left flank.
General Lee guessed the plan and countered it with classic daring. On the 1st of May Confederate troops under Jackson advanced to meet the Union flanking move, halting it and provoking them to entrench. Early on the 2nd, Jackson then led most of his command via little known forest roads on their own wide flanking move and as the sun set, fell upon the unsuspecting Union XI corps at the right flank routing them utterly and driving them back amongst the rest of Hookers command. Tragedy followed victory for the Confederates, however, as Gen. Jackson leading his men forward in the failing light was actually shot by his own side, taken from the field and died some days later. On the 3rd, at Fredericksburg, Sedgewick was finally ordered to attack in strength against Early's weakend positions and managed to carry most of the infamous Mary's heights, but Lee managed to send reinforcements, since Hooker was already beaten, to stabilise the situation on the 4th. Although Sedgewick was in a good position, Hooker ordered the Union withdrawal.

The thick woodland known as the Wilderness around the small farm of Chancellorsville. ( miles west of Fredericksburg, Virginia, USA (USA)