England (Britons) and France (Gauls) were both occupied by the Romans. The same can be said the Vikings who, having run out of herring, turned their summer holiday habit of sacking monasteries in England, France and Ireland into an invasion and occupation. In England and France paying Danegeld to make the raiding Vikings go away proved pointless. In 1016 England fell under the rule of Cnut King of Denmark and Norway, who unified the Anglo-Saxon kingdoms that emerged in the anarchy after the Romans left. In Northern France, Rollo (a Viking of unknown heritage) took control of Frankish lands including Bayeux and Rouen and in 918 was granted additional land by Charles the Simple, King of West Francia. This allowed Rollo to create modern day Normandy (land of the Norsemen) on the condition he stop raiding, became a Christian and protected West Francia against future Viking raids. It’s not clear if Rollo ever took a title, but he is popularly known as the first duke of Normandy.