Hundred Years' War
The Hundred Years' War was a series of conflicts waged from 1337 to 1453 by the House of Plantagenet, rulers of the Kingdom of England, against the French House of Valois, over the right to rule the Kingdom of France. Each side drew many allies into the war. It was one of the most notable conflicts of the Middle Ages, in which five generations of kings from two rival dynasties fought for the throne of the largest kingdom in Western Europe. The war marked both the height of chivalry and its subsequent decline, and the development of strong national identities in both countries.
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.