Dover Castle is a medieval castle in Dover, Kent, England. It was founded in the 12th century and has been described as the "Key to England" due to its defensive significance throughout history
During the reign of Henry II the castle began to take recognisable shape. The inner and outer baileys and the great Keep belong to this time. The keep was one of the last rectangular keeps ever built. In 1216, a group of rebel barons invited Louis VIII of France to come and take the English crown. He had some success breaching the walls but was unable ultimately to take the castle.
The castle, secret tunnels and surrounding land are now owned by English Heritage and the site is a major tourist attraction. The Lord Warden of the Cinque Ports is officially head of the castle, in his conjoint position of Constable of Dover Castle, and the Deputy Constable has his residence in Constable's Gate.