Video games are not there to give you history, I get that but I think it a shame that the in Assassin's Creed Valhalah that they made Alfred the Great your protagonists. He and his kin were really the first true kings of a united England.
Alfred the Great (Old English: Ælfrēd); between 847 and 849 – 26 October 899) was King of Wessex from 871 to c. 886 and King of the Anglo-Saxons from c. 886 to 899. After ascending the throne, Alfred spent several years fighting Viking invasions. Likely by today's standards we might not have liked this dude. Yet, he united England and they system the set up united Celtic, Angles, Saxons and Dane societies together. Coalesces of those groups was necessary for the England we know today to grow as a nation.
Which is not to say Viking aren't interesting too. This era of history is very interesting especially if you want to do a game centered around Europe. If not a viking game, then the other option is a Charlemagne, (800-814). And, you don't do a Charlemagne or "Holy Roman Empire game"; because they you start inciting Nazis, who refer to that part of history as the First Reich - yikes! So- yeah- let's stick with the raping & pillaging Vikings, who have history with LESS baggage!!!
I look forward to this Assassin's Creed game. You can't go wrong with vikings, pirates, or ninjas for a game.