Chester William Nimitz, Sr. (; February 24, 1885February 20, 1966) was an American fleet admiral of the United States Navy. He played a major role in the naval history of World War II as Commander in Chief, United States Pacific Fleet (CinCPac), for U.S. naval forces and Commander in Chief, Pacific Ocean Areas (CinCPOA), for U.S. and Allied air, land, and sea forces during World War II.