One of the most interesting plot twists in ‘The Lost Kingdom’ was the fact that Uhtred was raised by the Danes, as it shaped a lot of what was to come for him in the series.
In the first season, Uhtred was initially named Osbert but was raised by Vikings after his father lost to Ragnar. His loyalty is continuously tested throughout the series as he is made to choose sides- whether to fight with the Danes or the Anglo-Saxons.
While this is a major part of the plot of ‘The Lost Kingdom,' there is no evidence that the real Uhtred shared a similar backstory.
Netflix is currently streaming the fifth and final installment of ‘The Lost Kingdom’ and if you need a similar fix, check out books that inspired the series- particularly ‘Warriors of the Storm,’ and the ‘Flame Bearer,’ which are the ninth and tenth installments in ‘The Saxon Stories.’