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 By the end of the century, however, the castle was increasingly regarded as out of date from a military perspective.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 powers of muster", and the Constableship of Dover Castle, later added (1267) to the Warden's office, enabled him to keep a garrison and administrative staff, including the Clerk and the Lieutenant of the Castle. The coat of arms of the Cinque Ports first appeared in 1305, second amongst the earliest English known heraldic emblems, predating even the coat of arms of the City of London. The coat of arms of the Cinque Ports displays three ships' hulls and three lions conjoined to these hulls, all in gold. These may originally have been "Gules three lions passant gardant in pale "