Who was Ansgar?

We are unusually well informed about Ansgar (801-865); his pupil Rimbert wrote the story of his life in the Vita Ansgari. Ansgar received his education as a priest in the northern France town Corbie, from where he was sent to the newly established Abbey of Corvey in 823. His first missionary journey in 826 led Ansgar to Denmark. In 829 he traveled to Sweden. Louis the Pious sent him to the future missionary stronghold Hammaburg in 834, where he remained until the Vikings destroyed it in 845. He escaped to Bremen where he became the local bishop. He died there in 865.