The Treaty of Saint-Clair-sur-Epte

Saint-Clair-sur-Epte

Saint-Clair-sur-Epte is a commune in the Val-d'Oise department in Île-de-France in northern France.Henry I of England seized the castle of Saint-Clair-sur-Epte in 1118. -See also:*Treaty of Saint-Clair-sur-Epte*Epte*Communes of the Val-d'Oise department...

was signed in the autumn of 911 between Charles III of France and Rollo

Rollo of Normandy

Rollo , baptised Robert and so sometimes numbered Robert I to distinguish him from his descendants, was a Norse nobleman of Norwegian or Danish descent and founder and first ruler of the Viking principality in what soon became known as Normandy...

, the leader of the Viking

Viking

The term Viking is customarily used to refer to the Norse explorers, warriors, merchants, and pirates who raided, traded, explored and settled in wide areas of Europe, Asia and the North Atlantic islands from the late 8th to the mid-11th century.These Norsemen used their famed longships to...

s, to settle the Normans

Normans

The Normans were the people who gave their name to Normandy, a region in northern France. They were descended from Norse Viking conquerors of the territory and the native population of Frankish and Gallo-Roman stock...

 in Neustria

Neustria

The territory of Neustria or Neustrasia, meaning "new [western] land", originated in 511, made up of the regions from Aquitaine to the English Channel, approximating most of the north of present-day France, with Paris and Soissons as its main cities...

 and to protect Charles' kingdom from any new invasion by the "northmen". No written records survive concerning the creation of the Duchy of Normandy

Duchy of Normandy

The Duchy of Normandy stems from various Danish, Norwegian, Hiberno-Norse, Orkney Viking and Anglo-Danish invasions of France in the 9th century...

. In addition, Rollo was to be baptised, marry Gisele, the illegitimate daughter of Charles, and become the vassal of the king. .