Chivalry and Betrayal: The Hundred Years' War
In 1435 Bedford died and sworn enemies Charles VII and Phillip, Duke of Burgundy joined forces to get the English out and with Henry VI reluctance to wage war and to maintain peace by marrying Margaret of Anjou. Charles had no intention of peace and used cannon and sieges to retake France and Normandy culminating in the defeat of the English at the Battle of Castillon in the last English territory of Gascony ending the hundred years war.
War of the Breton Succession
Up to this point, the succession crisis had been a purely internal affair. But to complicate things further, the Hundred Years' War between England and France had broken out four years earlier, in 1337. In 1341, there was truce between the two countries, but there was little doubt that hostilities would be renewed when the truce ended in June 1342. Thus, when rumours reached Philip VI of France that John of Montfort had received English agents, the French Crown naturally took a more direct interest in the situation. Charles of Blois became the official French candidate. Whatever had been his original intentions, John of Montfort was now forced to support Edward III of England as King of France.