OP is talking about OTL.
By 1,100 AD Vikings ruled Russia, Normandy, England, Iceland, Greenland and settled parts of the North American coast.
Rollo the Viking gained respectability when he gained control of part of the Norman coast just before the millennium. His Grandson William the Coqueror gained control of England in 1066.
Meanwhile "Russ" gained control of Kiev. The Kievian Russ dominated Russian politics for the next thousand years.
In most cases, only Viking men/warriors emigrated. They killed off or exiled the former male ruling class. Then Vikings took local wives. Those wives taught the children of (new) Viking rulers local languages and customs. In the end, Vikings only made limited genetic contributions and much Viking culture was over-shadowed by local culture.
My recent studies of Vikings in Greenland revealed that most Viking settlers were just looking for farmland.