The Normans (adapted from the name "Northmen" or "Norsemen") were Scandinavian invaders (especially Danish Vikings) who began to occupy the northern area of France now known as Normandy in the latter half of the 9th century. Under the leadership of Hrolf Ganger, who adopted the French name Rollo, they swore allegiance to the king of France (Charles the Simple) and received the small and lower Seine area from him in 911 which they later expanded to become the Duchy of Normandy.