Archbishopric of Magdeburg

The Archbishopric of Magdeburg was a Latin Catholic archdiocese (969–1552) and Prince-Archbishopric (1180–1680) of the Holy Roman Empire centered on the city of Magdeburg on the Elbe River. Planned since 955 and established in 967, the archdiocese had de facto turned void since 1557, when the last papally confirmed prince-archbishop, the Lutheran Sigismund of Brandenburg came of age and ascended to the see.

Source: Wikipedia — Archbishopric of Magdeburg (CC BY-SA 4.0)