The Breton War of Succession was fought 1341–1364. The parties were the half-brother of the last duke, John of Montfort (supported by the English) and his niece, Joanna of Penthièvre, who was married to Charles of Blois, nephew of the king of France. This protracted conflict, a component of the Hundred Years' War, has passed into legend (see for example Combat of the Thirty and Bertrand de Guesclin). Its outcome was decided at the Battle of Auray in 1364, where the House of Montfort was victorious over the French party. After the first Treaty of Guérande, Joanna of Penthièvre abdicated her claims to the dukedom in favour of John the Conqueror. A modified form of Salic law was introduced in Brittany as a result.