Hundred Years' War (1415–53)
By 1449, the French had retaken Rouen. In 1450 the Count of Clermont and Arthur de Richemont, Earl of Richmond, of the Montfort family (the future Arthur III, Duke of Brittany) caught an English army attempting to relieve Caen at the Battle of Formigny and defeated it. The English army was attacked from the flank and rear by Richemont's force just as they were on the verge of beating Clermont's army. The French proceeded to capture Caen on July 6 and Bordeaux and Bayonne in 1451. The attempt by Talbot to retake Guyenne, though initially welcomed by the locals, was crushed by Jean Bureau and his cannons at the Battle of Castillon in 1453 where Talbot had led a small Anglo-Gascon force in a frontal attack on an entrenched camp. This is considered the last battle of the Hundred Years' War.
Brittany
The Breton War of Succession, a local episode of the Hundred Years' War, saw the House of Blois, backed by the French, fighting with the House of Montfort, backed by the English. The Montforts won in 1364 and enjoyed a period of total independence until the end of the Hundred Years' War, because France was weakened and stopped sending royal envoys to the Court of Brittany. English diplomatic failures led to the Breton cavalry commanders Arthur, Comte de Richemont (later to become Arthur III, Duke of Brittany) and his nephew Peter II, Duke of Brittany playing key roles on the French side during the deciding stages of the War (the Battle of Patay, the Treaty of Arras (1435), the Battle of Formigny and the Battle of Castillon). However, Brittany lost the Mad War against France in 1488, mostly because of its internal divisions which were exacerbated by the corruption at the court of Francis II, Duke of Brittany. Indeed, some Breton lords were fighting on the French side.