 Complete the following phrase:  On 23 January 1628, at the age of 13, August was appointed administrator of the Archbishopric of Magdeburg by its Chapter to replace the current holder of that title, Christian Wilhelm of Brandenburg. By that time, August had already served three years as coadjutor. Nevertheless, he could not assume his post: on 20 May 1631, after seven months of siege and plundering during the 