In 1337, the 25-year-old King Edward III (1327-77), who was already lord of the Duchy of Guyenne in southwest France, laid claim to the French Crown. Edward's contention was based on a claim that ran through his mother, Isabel, the sister of the three previous Valois kings of France, and who had been wrongly disinherited by her cousin, French King Philip VI. For the next hundred years this family conflict was fought out with a mixture of chivalry and savagery. French and English lords fought one another with honor and civility ... and their subjects were butchered unmercifully ...