The Siege of Arundel took place during the First English Civil War, from 19 December 1643 to 6 January 1644, when a Royalist garrison surrendered to a Parliamentarian army under Sir William Waller. At the end of 1642, South-East England was largely controlled by Parliament, with pockets of Royalist support in Hampshire and Kent. In an October 1643 offensive led by Sir Ralph Hopton, the Royalists advanced into Sussex, where a small garrison at Arundel Castle surrendered without fighting on 2 December.