On April 27, Maj. Gen. Joseph Hooker led the V, XI, and XII Corps on a campaign to turn the Confederate left flank by crossing the Rappahannock and Rapidan Rivers above Fredericksburg. Passing the Rapidan via Germanna and Ely's Fords, the Federals concentrated near Chancellorsville on April 30 and May 1. The III Corps was ordered to join the army via United States Ford. Sedgwick's VI Corps and Gibbon's division remained to demonstrate against the Confederates at Fredericksburg. In the meantime, Lee left a covering force under Maj. Gen. Jubal Early in Fredericksburg and marched with the rest of the army to confront the Federals. As Hooker's army moved toward Fredericksburg on the Orange Turnpike, they encountered increasing Confederate resistance. Hearing reports of overwhelming Confederate force, Hooker ordered his army to suspend the advance and to concentrate again at Chancellorsville. Pressed closely by Lee's advance, Hooker adopted a defensive posture, thus giving Lee the initiative. On the morning of May 2, Lt. Gen. T.J. Jackson directed his corps on a march against the Federal left flank, which was reported to be "hanging in the air." Fighting was sporadic on other portions of the field throughout the day, as Jackson's column reached its jump-off point. At 5:20 pm, Jackson's line surged forward in an overwhelming attack that crushed the Union XI Corps. Federal troops rallied, resisted the advance, and counterattacked. Disorganization on both sides and darkness ended the fighting. While making a night reconnaissance, Jackson was mortally wounded by his own men and carried from the field. J.E.B. Stuart took temporary command of Jackson's Corps. On May 3, the Confederates attacked with both wings of the army and massed their artillery at Hazel Grove. This finally broke the Federal line at Chancellorsville. Hooker withdrew a mile and entrenched in a defensive "U" with his back to the river at United States Ford. Union generals Berry and Whipple and Confederate general Paxton were killed; Stonewall Jackson was mortally wounded. On the night of May 5-6, after Union reverses at Salem Church, Hooker recrossed to the north bank of the Rappahannock. This battle was considered by many historians to be Lee's greatest victory.