Athelstan is a monk who turned from Christianity into the mythology world of the Vikings. He became a slave of Ragnar in the first season. In the second season he gets involved into a change from the Viking way into the Christianity again when he becomes the advisor of King Eckbert. We are not sure what is going to happen with him as character.
According to the history of the real Athelstan he is the one who fight every Viking out of England and then become King after all the Vikings are gone and there is a land to rule. He became the first king of England.
He is born 28 December 1989. He has played in Les Miserablé the film version but is better known for his role Athelstan in Vikings. He is an stage and film actor. He is English. Can be found on Twitter @gblagden and You Tube https://www.youtube.com/user/gblagden His next role will be King Louis XIV in Versailles. http://en.wikipedia.org/wiki/George_Blagden