Usually a change in culture after the Vikings have been somewhere means they massacred the locals. Case in point, Orkney Island.
My first question is the DNA from the locals the same pre and post “mid to late medieval period”?
The Vikings also settled some of those islands after they’d been abandoned, after earlier populations died out, or were the first settlement that has been found to date. They were happy enough to just kill all the men and take all the women. I’ve noticed that when talking with people who have also had their DNA done.
http://www.freerepublic.com/tag/skarabrae/index
Oh great. Now I’ll have to not only apologize for being white but for my Scandinavian heritage too.