The Battle of Shiloh, fought on April 6–7, 1862, resulted in a Union victory. Union forces under Major General Ulysses S. Grant, reinforced by Major General Don Carlos Buell's troops, successfully repelled the Confederate army commanded initially by General Albert Sidney Johnston and later by General P.G.T. Beauregard after Johnston was mortally wounded on the first day. Despite initial Confederate gains and a surprise attack, the Union counterattacked on the second day, forcing the Confederates to retreat to Corinth, Mississippi. The battle was one of the bloodiest of the Civil War up to that point, with heavy casualties on both sides, but it ended the Confederate hopes of blocking the Union advance into Mississippi and marked a turning point in the Western Theater of the war