In 843, three years after the death of Louis the Pious, the Frankish Empire was divided among the three sons of the emperor by the Treaty of VerdunHammaburg now belonged to East Francia, Louis the German's part of the empire. The new borderline cut right through the archdiocese of Cologne and excluded the diocese Bremen, which had previously belonged to Cologne. With the appointment of his confidant Ansgar as Bishop of Bremen, Louis created a fait accompli. Now located in Bremen, Ansgar fulfilled his mission, which he originally intended to do from Hammaburg, the proselytization of the north. As a result, and despite strong protests from Cologne, Bremen veered increasingly away from its former archdiocese by the river Rhein. For proselytizing the Danes and Swedes the diocese Bremen tied itself intrinsically to Hamburg and Nordalbingia.