Following its defeat at Fredericksburg in December 1862, the Union Army of the Potomac spent the winter in Stafford County. Across the Rappahannock River, Robert E. Lee’s Army of Northern Virginia held a defensive position covering a 25-mile stretch of the river. In January 1863, President Lincoln promoted General Joseph Hooker to command the army opposite Fredericksburg and charged him with defeating Lee. On April 27, Hooker sent a force across the river below Fredericksburg to distract the Confederate commander while the rest of his army marched north and west, crossed the Rapidan and Rappahannock rivers, and moved in behind Lee. On April 30, the Union army began concentrating at Chancellorsville, a former inn located near a small crossroads there. Outnumbered two-to-one, Lee left a small defense at Fredericksburg and turned toward the threat from the west. Confederates formed a line of defense on the ridge and awaited the arrival of General Thomas “Stonewall” Jackson’s divisions. Once assembled, they would be strong enough to move forward against Hooker’s army at Chancellorsville. In the fighting that followed, over 30,000 men became casualties, but Lee won what has been considered his greatest victory of the war.