Allegiance in the 14th century was still given to a person, not a nation, and the great territorial lords of duchies and counties felt themselves free to make alliances as if almost autonomous. The Harcourts of Normandy and the Duke and other lords of Brittany, for various reasons, did just that.
“The claim to the French crown gave an excuse of legality to any vassal of France whom Edward could recruit as an ally. If he, not Philip, were the rightful King of France, a vassal could transfer his homage on the ground that it had simply been misplaced. Allegiance in the 14th century was still given to a person, not a nation, and the great territorial lords of duchies and counties felt themselves free to make alliances as if almost autonomous. The Harcourts of Normandy and the Duke and other lords of Brittany, for various reasons, did just that. Edward’s claim through his mother gave him the one thing that made his venture feasible—support within France and a friendly beachhead. He never had to fight his way in. In either Normandy or Brittany this situation was to last forty years, and at Calais, captured after the Battle of Crécy, it was to outlast the Middle Ages.”
