albert of mainz archbishopric of magdeburg archdiocese of bremen archduke leopold wilhelm of austria bishopric of hildesheim bishopric of ratzeburg bremen calenberg charlemagne county of blankenburg diocese electorate of hanover german language germany goslar government grubenhagen halberstadt hamburg harz holstein holy roman empire lower saxon circle lutheranism margraviate of brandenburg mecklenburg mecklenburg-schwerin mecklenburg-strelitz middle ages nordhausen osterwieck peace of westphalia prince-bishop principality of halberstadt protestant reformation regenstein roman catholic church saxe-lauenburg saxons secularization theocracy