Uhtred is based on Uhtred the Bold, who was an ealderman of Northumbria. But the big difference here is the Uhtred the Bold was born like 150 years after the events of the show.

I haven't seen vikings, but now I'm disappointed that it's not historical. Ironic given the show was basically the History Channel's small glimpse of redemption after they went all in on reality tv.

I finished the Last Kingdom and played the game Assassin's Creed Valhalla, both which feature real locations and real people from that era.

As people already mentioned, post-Roman Britannia was a series of Anglo-Saxon kingdoms all fighting for power.

If you read up the history on Alfred the Great, it'll fall in line with the plot for the the show.