The islands became subject to the Kingdom of England following the conquest of England by William, Duke of Normandy in 1066. However, in 1202, in a conflict with King John, Philip Augustus of France, claiming feudal overlordship of Normandy, summoned the English King to answer charges or forfeit all lands which he held in fee of the King of France. John refused to appear and, in 1204, Philip occupied continental Normandy, although he failed in his attempts to occupy the islands in the Channel. The 1259 Treaty of Paris confirmed the loss of Normandy but the retention of the "islands (if any) which the King of England should hold" under suzerainty of the King of France. The vassalage requirement was extinguished in the Treaty of Calais of 1360.