Held in the Cotton Manuscripts collection, this coloured bird's eye view of “A Castle for the Downs” is most likely to be an early design for the castles of Walmer and Sandown. These were two of several castles built along the south coast of England to protect the Downs anchorage and also the Kent coast itself. These defences became necessary after a peace treaty was signed by King Francis I of France (1494–1547) and Charles V, Holy Roman Emperor and King of Spain (1500–1558) in 1538, making an invasion of England probable. England and France were ancient enemies and the catholic Charles V, nephew of Catherine of Aragon, was angered by King Henry VIII’s decision to divorce his aunt. Henry’s dissolution of the monasteries provided him with enormous wealth with which he was able to commission surveys of the vulnerable coastline and build defence fortifications. In order to protect the ‘invasion beaches’ and the newly completed dockyards at Portsmouth, a survey of the south coast was made in February 1539. Drawn on vellum this plan dates from 1539, the year of this survey.
The circular formation of the castle, with circular bastions and gun ports with some external splay, show that defence was the primary concern. The drawing depicts openings for 92 guns in four tiers, over twice as many openings as were actually provided in three tiers. It is likely that this drawing came from the drawing office of the Hampton Court team responsible for the construction of the castles in the Downs. Richard Benese was the surveyor, with William Clement and Christopher Dickenson working as master carpenter and master mason.