The Norsemen/Vikings were all over what now is Ireland, Scotland, and England, not to mention the lands of the Rus, the continually warring tribes of which they pacified and unified, after a fashion, creating Russia. The Normans invaded northern region of what now is France, and settled there in numbers such that Charlemagne granted them what we know as Normandy. Floating down rivers from the north, they were able to trade with the Arabs.
And the Norsemen/Vikings in Normandy, known as the Normans, are the ones that conquered England and Ireland in 1066.