Athelstan is a monk that was taken hostage during Ragnar’s first raid on English soil. The fact that Athelstan can speak Ragnar’s language is his saving grace and Ragnar chooses him as his slave. Athelstan is played by English actor George Blagden.
In Season 1, Athelstan grapples with his new life in the viking lands. Although he does become close to Ragnar who eventually frees him from being a slave. However, his life is threatened once more when they make a pilgramage to Uppsala. Athelstan is supposed to be a human sacrifice to the gods but escapes with his life once it is revealed he is still a christian.
In Season 2, Athelstan is still trying to marry his relationship between his Christian beliefs and his new vikings beliefs. After he returns to England to raid with Ragnar, he ends up staying there and is influential in saving Rollo’s life. Eventually though, Athelstan returns to the viking world.
(Photo Credit: History Channel, Metro-Goldwyn-Mayer Studios Inc.)