The Duchy of Normandy grew out of the 911 Treaty of Saint-Clair-sur-Epte between King Charles III of West Francia and Rollo, leader of the Vikings. The duchy was established under  Richard II in c. 996. From 1035 to 1135 it was held by the Norman kings of England and then, after 15 years of government by Stephen of Blois and Geoffrey Plantagenet, it was held by the Angevin kings of England from 1150 to 1204. Normandy was conquered by Philip II of France in 1204 and remained disputed territory until the Treaty of Paris of 1259, when the English sovereigns ceded their claim, except for the Channel Islands.