The
Treaty of Saint-Clair-sur-Epte, between
Charles the Simple (King Charles III of France) and
Rollo, the leader of the
Vikings, was signed in autumn 911. The treaty permitted the
Normans to settle in
Neustria in return for their protection of Charles' kingdom from any new invasion by the "northmen". No written records survive concerning the creation of the
Duchy of Normandy.