When the peace was sealed in 1365, it was stipulated that the Montfort branch would succeed in Brittany subject to the restrictions of
Salic law and in the case of their male line going extinct, the heirs of
Joanna of Penthièvre will succeed the last male Montfortist duke. The Breton ducal house and many Breton noble families had followed a semi-Salic tradition which permitted a daughter to inherit from her father. The Blois-Penthièvre family received more estates in Brittany as partial compensation. Brittany retained its autonomy, or rather independence, although continuously giving lip service to French sovereignty. After the
Breton War of Succession, Brittany still had links with the English through the
Earldom of Richmond, until the
Wars of the Roses. in the estuary of the river
Rance in Brittany was built between 1369 and 1382 by
John V, Duke of Brittany to the Rance at a time when the city of
Saint-Malo did not recognize his authority.
John IV, Duke of Brittany was deserted by his nobles in 1373 and left for exile in England.
Louis I, Duke of Anjou, brother of
Charles V of France, and a son-in-law of the deposed Penthièvre Duchess Joanna, was appointed lieutenant-general of Brittany by the king, who in 1378 sought to annex Brittany to France, which provoked the Bretons to recall John IV from exile. The second Treaty of
Guérande (1381) established Brittany's neutrality in the Anglo-French conflict, although John continued to make homage to King of France. In 1420,
John V, Duke of Brittany was kidnapped by Olivier de Blois, count of Penthièvre, son of Joanna of Penthièvre. John's wife,
Joan of France besieged the rebels and set free her husband, who confiscated the Penthièvre's goods. According to the succession order enacted, in 1457 Duke Peter II was succeeded by his elderly uncle
Arthur de Richemont instead of his sister Isabelle de Bretagne-Montfort (who married into the Laval family and from whom the future Chabot branch of the
Rohan family descends). In 1465, Francis II took the county of Penthièvre from its heiress, Nicole de Bretagne-Blois, thus again undermining the rival family's position in Brittany. However, the last male Montfort,
Francis II, Duke of Brittany (died in 1488) prepared for succession by his daughter
Anne of Brittany – thus, the first female Montfort rulership abrogated the rights of genealogically more senior Penthièvre family (Catholics) as well as those of Rohan family (future Huguenots) but was consistent with the traditions of semi-Salic Brittany and had the support of the Breton nobles in the Estates of Brittany. In the last years of Francis II, war with France continued and he was defeated in 1488. This last duke of independent Brittany was forced to submit to a treaty giving the King of France the right to determine the marriage of the Duke's daughter, Anne, a young girl 12 years old, and now the sole heir to the Duchy based on a
de facto return to the Duchy's semi-Salic traditions. ==Ruled by the King of France==