Duchy of Normandy

The Duchy of Normandy grew out of the 911 Treaty of Saint-Clair-sur-Epte between King Charles III of West Francia and the Viking leader Rollo. The duchy was named for its inhabitants, the Normans.

From 1066 until 1204, as a result of the Norman Conquest of England, the dukes of Normandy were usually also kings of England, the only exceptions being Dukes Robert Curthose (1087–1106), Geoffrey Plantagenet (1144–1150), and Henry II (1150–1152), who became king of England in 1154.

In 1202, Philip II of France declared Normandy forfeit to him and seized it by force of arms in 1204 (with the exception of the Channel Islands). It remained disputed territory until 1259, when the English sovereign ceded his claim to mainland Normandy which was absorbed into the French royal domain.