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.
Mary of Waltham
Seven years previously, King Philip VI of France attempted to confiscate the Duchy of Guyenne (also referred to as Aquitaine) from Edward III – an event that traditionally marks the beginning of the Hundred Years' War – after which Edward used military force, diplomacy and marital links to strengthen his claim to the French throne. In the Duchy of Brittany succession dispute, he supported John of Montfort since a close alliance to the English crown with Brittany would give Edward access to the port of Brest for use by English troops. When Montfort was captured, his wife, Joanna of Flanders, took over the campaign and, during the siege of Rennes, received military support from Edward. In return, she promised her son John (later John IV, Duke of Brittany) to one of his daughters.