He then turned his attention against Charleston, South Carolina. Initially successful in an attack on the southern end of Morris Island on July 10, Gillmore had enough confidence to assault Fort Wagner on the north end of the island. The following day he launched the first attack on Fort Wagner which was defeated. He assembled a larger assault force and with the assistance of John A. Dahlgren's naval fleet planned a second attack. On July 18, 1863 Gillmore's troops were repulsed with heavy losses in the Second Battle of Fort Wagner. Gillmore's divisional commander, General Truman Seymour was wounded and two brigade commanders, George Crockett Strong and Haldimand S. Putnam were killed in the attack.