Deal Castle is an artillery fort constructed by Henry VIII in Deal, Kent, between 1539 and 1540. It formed part of the King's Device programme to protect against invasion from France and the Holy Roman Empire, and defended the strategically important Downs anchorage off the English coast. Comprising a keep with six inner and outer bastions, the moated stone castle covered 0.85 acres (0.34 ha) and had sixty-six firing positions for artillery. It cost the Crown a total of £27,092 to build the three castles of Deal, Sandown and Walmer, which lay adjacent to one another along the coast and were connected by earthwork defences. The original invasion threat passed but, during the Second English Civil War of 1648–49, Deal was seized by pro-Royalist insurgents and was only retaken by Parliamentary forces after several months' fighting.