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.
House of Valois
Because diplomacy and negotiation had failed, Edward III would have to back his claims with force to obtain the French throne. For a few years, England and France maintained an uneasy peace. Eventually, an escalation of conflict between the two kings led to the confiscation of the duchy of Aquitaine (1337). Instead of paying homage to the French king, as his ancestors had done, Edward claimed that he was the rightful King of France. These events helped launch the Hundred Years' War (1337-1453) between England and France. Though England failed to win that prolonged conflict, English and British Monarchs until the late 18th Century continued to maintain, at least formally, a claim to the French throne.