In 1643, during the English Civil War, Parliamentary forces under Sir William Waller besieged Royalist forces under Sir Ralph Hopton in Devizes. However the siege was lifted by a relief force from Oxford under Henry Wilmot, 1st Earl of Rochester and Waller's forces were almost totally destroyed at the Battle of Roundway Down. Devizes remained under Royalist control until 1645, when Oliver Cromwell attacked and forced the Royalists to surrender. The castle was destroyed in 1648 on the orders of Parliament, a process known as slighting, and today little remains of it.