In the Western Theater, much of the fighting happened along the Mississippi River. Ulysses S. Grant was an important Union general in the West. The Confederates tried to send their soldiers into the state of Kentucky in the summer of 1861. In the early months of 1862, the Union Army made the Confederates retreat from Kentucky and from western Tennessee. They tried to recapture western Tennessee by attacking Grant's army at the Battle of Shiloh, but Grant won the battle. The Confederates then tried to send their soldiers into eastern Kentucky in the fall of 1862 but lost the Battle of Perryville and then left Kentucky.