The Medium Tank M3 was an American tank used during World War II. In Britain the tank was called by two names based on the turret configuration. Tanks employing US pattern turrets were called the "Lee", named after Confederate General Robert E. Lee. Variants using British pattern turrets were known as "Grant", named after U.S. General Ulysses S. Grant.Design commenced in July 1940 and the first M3s were operational in late 1941. The U.S.