On April 27, 1863, Maj. Gen. Joseph Hooker launched a turning movement designed to pry Robert E. Lee's Army of Northern Virginia out of its lines at Fredericksburg. The manuever was successful and by April 30, elements of Hooker's Army of the Potomac had reached the crossroads of Chancellorsville, 12 miles in Lee's rear. Hooker stood poised to strike a blow at the Confederates. Apprised of Hooker's march Lee left a covering force at Fredericksburg and marched to meet the main threat. Fighting erupted on May 1 with the Federals ultimately retiring back to Chancellorsville. With the initative in hand, Lee decided to divide his army again and send Lt. Gen. Thomas J. "Stonewall" Jackson on a march to strike Hooker's right flank. The following evening, Jackson's men assailed Maj. Gen. Oliver O. Howard's XI Corps and caved in the Union line. That night, Jackson was wounded by friendly fire. He succumbed to pneumonia eight days later. Lee renewed his attack early on May 3 and dislodged Hooker from Chancellorsville. At the height o of victory, he was forced to divide his army for the third time to confront Maj. Gen. John Sedgwick's VI Corps which had broken through at Fredericksburg. The Confederates brought Sedgwick's advance to a standstill at Salem Church. Stalled on two fronts, Hooker decided to retreat and abandon his campaign on the night of May 5. The battle emboldened Lee and inspired him to launch a second northern invasion in June 1863.