Loss of Normandy (1204)

Since the Norman Conquest the English kings had always understood their realm as a cross-Channel kingdom. After Philip II's invasion of Normandy in 1203/04 the duchy was at once joined to the French royal domain. King John virtually lost the duchy to the French king, and his son, Henry III formally surrendered all claims to the region at the Treaty of Paris in 1259. Henry V annexed Normandy again in 1419, but the area was finally returned to France in 1450, except Calais and the Channel Islands. The loss of 1204 had far-reaching consequences on those nobles who held lands on both sides of the Channel. According to feudal law, only very few could be vassals of the English and the French king at the same time, e.g. the Earl of Leicester and the Earl of Pembroke. The others had to decide whether they were French or English aristocrats.