Designed to be a place of leisure, between the seaside and a forest full of game for hunting, the castle's first logis seigneurial (seigniorial house) dates from the beginning of the 13th century. The castle was fortified and enlarged, at the end of 14th century, when the heirs of the duchy had to fight to keep their assets (Brittany was not yet fully united to France and did not become so until 1514), after the castle was taken by Bertrand du Guesclin, the infamous Constable of France. John V and John VI constructed a new seigniorial residence block with a large, new corner tower known as the Tour Neuve. A casemate was added at the end of 15th century to protect artillery pieces.