Confederate forces attacked Union forces under General Ulysses S. Grant at Shiloh, Tennessee. By the end of the day, the federal troops were almost defeated. Yet, during the night, reinforcements arrived, and by the next morning the Union commanded the field. When Confederate forces retreated, the exhausted federal forces did not follow. Casualties were heavy—13,000 out of 63,000 Union soldiers died, and 11,000 of 40,000 Confederate troops were killed.