Dei et Apostolicae Sedis Gratia: Über die Entstehung von Personenherrschaft in den Bistümern Bremen und Verden im frühen Mittelalter und die Rezeption dieser Zeit in liturgischen Schriften des Erzbischofs Christoph von Braunschweig-Lüneburg.

This works focuses on the political history of the bishopries of Bremen and Verden (North-Western Germany) during their first 300 years, beginning as unimportant mission-territories until their establishment as confident territories of the Holy German Empire in the 12th century. The second part is emphasizing on the reflection this time has found in liturgical prints during the reign of Archbishop Christoph of Brunswick, whose reign can be seen as a borderline between catholic middle ages and the beginning reformation.