On this day in 1863, the Battle of Chancellorsville begins in Virginia. Earlier in the year, General Joseph Hooker led the Army of the Potomac into Virginia to confront Robert E. Lee's Army of Northern Virginia. Hooker had recently replaced Ambrose Burnside, who presided over the Army of the Potomac for one calamitous campaign the previous December: the Battle of Fredericksburg. At that conflict, the Yankees amassed over 14,000 casualties while the Rebels suffered some 5,000 casualties.
After spending the spring retooling his army and boosting their sinking morale, Hooker advanced toward the Confederate army, possessing perhaps the greatest advantage over Lee that any Union commander had during the war. His force numbered some 115,000 men, while Lee had just 60,000 troops present for service. Absent from the Confederate army were two divisions under General James Longstreet, which were performing detached service in southern Virginia.
Hooker had a strategically sound plan. He intended to avoid the Confederate trenches that protected a long stretch of the Rappahannock River around Fredericksburg. Placing two-thirds of his forces in front of Fredericksburg to feign a frontal assault and keep the Confederates occupied, he marched the rest of his army up the river, crossed the Rappahannock, and began to move behind Lee's army. The well-executed plan placed the Army of Northern Virginia in grave danger.
But Lee's tactical brilliance and gambler's intuition saved him. He split his force, leaving 10,000 troops under Jubal Early to hold the Federals at bay in Fredericksburg, and then marched the rest of his army west to meet the bulk of Hooker's force. Conflict erupted on May 1 when the two armies met in an open area beyond the Wilderness, the tangled forest just west of the tiny burgh of Chancellorsville. Surprisingly, Hooker ordered his forces to fall back into defensive positions after only limited combat, effectively giving the initiative to Lee. Despite the fact that his army far outnumbered Lee's, and had the Confederates clamped between two substantial forces, Hooker went on the defensive. In the following days, Lee executed his most daring battle plan. He split his army again, sending Thomas J. "Stonewall" Jackson further west around the Union's right flank. The crushing attack snapped the Union army and sent Hooker in retreat to Washington, D.C., and, perhaps more than any other event during the war, cemented Lee's invincibility in the eyes of both sides.