Vikings: Every Character Based On Real Historical Figures

Harald Finehair is based on Harald Fairhair, a prominent Viking who is credited with being the first person to unite all of Norway into one kingdom. Although his name is slightly altered, the fictional and historical characters have similar stories: they were both rejected by the woman they loved for not being important enough. Thus they vowed not to cut their hair until they had managed to claim the entirety of Norway as their kingdom. This also gave them their nicknames.

The real character was believed to have lived around the late 9th century AD to the early 10th century AD. This means that he would not have fought with Ragnar's sons and that he would not have been a leader of, and probably not have participated in, the Great Heathen Army as portrayed in the show.