 This was mainly due to Rollo, a Viking leader who seized what is now Normandy in 879, and formally in 911 when Charles the Simple of West Francia granted him the Lower Seine.This became a precursor to the Viking expansion that established important trade posts and agrarian settlements deep into Frankish territory, English territory, and much of what is now European Russian territory.The Vikings had taken control of most of the Anglo-Saxon kingdoms by the 870s, which was after the time of the Great Heathen Army that swept the Anglo-Saxon rulers away from power in 865.