Guy of Penthièvre French noble (1287–1331) Parents Arthur II, Duke of Brittany Marie, Viscountess of Limoges Children Joan, Duchess of Brittany Siblings John IV, Duke of Brittany Alice of Brittany John III, Duke of Brittany Beatrice of Brittany Pierre de Bretagne Marie de Montfort Jeanne de Dreux-Bretagne, Dame de Nogent-le-Rotrou Blanche de Montfort Partners Jeanne d'Avaugour Jeanne de Clisson