9th-century Latin-language Christian book by Rimbert
The Vita Ansgarii, also known as the Vita Anskarii, is the hagiography of saint Ansgar, written by Rimbert, his successor as archbishop in the Prince-Archbishopric of Bremen. The Vita is an important source not only in detailing Ansgar's Scandinavian missionary work, but also in its descriptions of the everyday lives of people during the Viking Age. Date. The Vita Anskarii was written sometime between the years 869 and 876. Author. Not much is known about Rimbert's life, the main source being the Vita Rimberrti, written 865–909.
https://en.wikipedia.org/wiki/Vita_Ansgarii