Isabella of Brittany French noble (1411–1444) Parents Joan of France, Duchess of Brittany John V Children Guy XV de Laval Hélène de Laval Yolande de Laval, Dame de Kergorlay Jeanne de Laval Pierre de Laval Louise de Laval Jean de Laval Siblings Peter II, Duke of Brittany Francis I, Duke of Brittany Gilles de Bretagne Partners Guy XIV de Laval