Chancellorsville, Battle Of

(May 1–5, 1863), in the American Civil War, bloody assault by the Union army in Virginia that failed to encircle and destroy the Confederate Army of Northern Virginia. Following the “horror of Fredericksburg” (December 13, 1862), the Confederate army of General Robert E. Lee and the Union force under General Joseph Hooker had spent the winter facing each other across the Rappahannock River