Oliver Cromwell with Sir Thomas Fairfax in command and Cromwell as Lieutenant-General of cavalry and second-in-command. At the critical Battle of Naseby in June 1645, the New Model Army smashed the King's major army. Cromwell led his wing with great success at Naseby, again routing the Royalist cavalry. At the Battle of Langport on 10 July, Cromwell participated in the defeat of the last sizeable Royalist field army. Naseby and Langport effectively ended the King's hopes of victory, and the subsequent Parliamentarian campaigns involved taking the remaining fortified Royalist positions in the west of England. In October 1645, Cromwell besieged and took
Devizes 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. From the 16th century Devizes became known for its textiles, initially white woollen broadcloth but later the manufacture of serge, drugget, felt and cassimere or Zephyr