Ansgar, Rimbert and the Forged Foundations of Hamburg-Bremen. [Church, Faith and Culture in the Medieval West]

Ansgar was at first an assistant in the northern mission led by Ebo of Rheims, and as such he received a legatio from the pope in 831; after Ebo's disgrace in 834, Ansgar was ordained a missionary bishop and granted the monastery of Turholt as a means of support by Louis the Pious. Not until 864 was Ansgar granted the title of missionary archbishop of the Danes and Swedes, as part of Louis the German and Pope Nicholas I's dispute with Lothar II and Gunthar, archbishop of Cologne (whose archdiocese, in principle, encompassed Bremen as a suffragan diocese).The quarrel ended in 865 (the year of Ansgar's death) and, with it, the political reason for Ansgar's archiépiscopal status.