Early in the American Civil War (1861–1865), the important Gosport Shipyard upstream from Craney Island on the Elizabeth River at Portsmouth fell into Confederate hands and the first Confederate ironclad warship CSS "Virginia" was converted from USS "Merrimack" there. The Confederates built a 20-gun battery on the island and berthed the "Virginia" there. This ship fought the first Union ironclad USS "Monitor" during the famous Battle of Hampton Roads on March 9, 1862, which was inconclusive as neither armored ship could defeat the other.