 The castle was built in two phases; Sir Robert Blake constructed the tower between 1651 and 1652 in the aftermath of the Parliamentary invasion of the islands at the end of the English Civil War, and Master Gunner Abraham Tovey added the gun platform during the War of Jenkins' Ear around 1739.The tower fell into disuse soon afterwards, and in the 21st century is managed by English Heritage and open to visitors.Cromwell's Castle is an artillery tower, built by Sir Robert Blake following the Parliamentary invasion of the Isles of Scilly in 1651.