There's a lot of northerners from a lot of era... People like to shout "viking" and act like it's a particular group of people who spoke the same language, had the same culture and came from the same place. While originating in Scandinavia these people settled and came from a wide range of places, had specific cultures and spoke variations of languages... They could be from Norway, Sweden, Denmark, Lithuania, Settled England, Scottland, Ireland, Iceland, Normandy, Russia and Greenland... So as I've likened it before, the Nords in TES are kinda like taking some dude, making his skin red and sticking a feather in his hair and saying he is a Native American from a particular era... when there were millions of Native Americans from thousands of tribes from many eras and places... i'm norwegian so i should know this: the vikings originaly came from norway, but as you said they settled everywhere so that'a why people think that englishmen where vikings and Russia? and even more hilarious is greenland, the vikings where the first people to inhabit greenland! so a viking could very well be what they are pointing at! AND as for the era it would have to be pretty early because vikings evolved into just regular farmers after a while