Walmer Castle against Charles' brother, King James II, the townsfolk of Deal seized Walmer Castle on behalf of William III, the Prince of Orange. By the end of the century, however, the castle was increasingly regarded as out of date from a military perspective. In the 18th century, Walmer Castle became the official residence of the Lord Warden of the Cinque Ports. The Lord Warden was originally a medieval title linked to five key ports along the coast of England; the position's prominence had faded, but it still retained important judicial and military functions. When Lionel Sackville, the Duke of Dorset, was
Lord Warden of the Cinque Ports (for England) dimidiating "Gules three ships' hulks in pale Or". The coat of arms of the Confederation of the Cinque Ports is set out on a red and blue background and traditionally represents the 14 "Corporate" Members. The creation and appointment of the Lord Warden, once among the most powerful appointments of the realm, by the Sovereign was instituted principally after the portsmen sided with the Earl of Leicester against King Henry III, in the Second Barons' War, and was intended to provide some central authority over the Cinque Ports, which were essentially otherwise independent of the King's sheriffs. It