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.
Duchy of Aquitaine
The Valois kings of France, claiming supremacy over Aquitaine, granted the title of duke to their heirs, the Dauphins, during 1345 and 1415: John II (1345–50), Charles VII (1392?–1401), and Louis (1401–15). French victory was complete with the Battle of Castillon of 1453. England and France nominally remained at war for another 20 years, but England was in no position to continue its campaign, due to its escalating internal conflicts. The Hundred Years' War was formally concluded with the Treaty of Picquigny of 1475. With the end of the Hundred Years' War, Aquitaine returned under direct rule of the king of France and remained in the possession of the king. Only occasionally was the title of "duke of Aquitaine" granted to another member of the dynasty, and then as a purely nominal distinction.