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 By the end of the century, however, the castle was increasingly regarded as out of date from a military perspective.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 of the Cinque Ports", they reflected an early concept that military service at sea constituted land tenure "per baroniam" making them "quasi" feudal barons. The early 14th-century treatise "Modus Tenendi Parliamentum" stated the Barons of the Cinque Ports to hold a place of precedence below the lay magnates but above the representatives of the shires and boroughs. Writs of summons to parliament were sent to the warden following which representative barons of the Cinque Ports were selected to attend parliament. Thus the warden's duty in this respect was similar to that of the sheriff who received the writs for distribution