Deserted by his nobles, duke John IV left for exile in England in 1373. The higher nobility of that time, like the house of Coetmen-Penthièvre, or the house of Rougé, descendants of the former kings of Brittany, strongly supported the Penthièvre side and nearly extinguished in the repeated fights between Montfort and Penthièvre's troops. The king of France Charles V named as lieutenant-general of Brittany his brother, the duke of Anjou (also a son-in-law of Joanna de Penthièvre). In 1378, the king of France sought to annex Brittany, 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 swear homage to Charles VI.