The Château de Suscinio or de Susinio is a French castle, built in the late Middle Ages, to be the residence of the Dukes of Brittany. It is located in the commune of Sarzeau in the département of Morbihan, near the coast of the Atlantic ocean. The spectacular site comprises the moated castle, a ruined chapel, a dovecote, and a few ruined outbuildings.
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.
From 1471 to 1483, the castle housed Jasper Tudor, Henry Tudor (later King Henry VII of England), and the core of their group of exiled Lancastrians, numbering about 500 by 1483. Since the castle could only house some 100 persons, the rest must have been billeted close about, in Kermoizin and other villages nearby.
Duke Francis II generously supported this group of exiled Englishmen against all the Plantagenet demands that he should surrender them. For 11 years, Suscinio was an armed camp, alert against any attempt to kidnap Jasper and Henry and return them to England where they were under attainder and would have been promptly executed as threats to Yorkist rule.