    Sentence 1: What dual titles did Frederick William  hold?    Sentence 2: Nearly 50,000 Huguenots established  themselves in Germany, 20,000 of whom were  welcomed in Brandenburg-Prussia, where they  were granted special privileges (Edict of Potsdam)  and churches in which to worship (such as the  Church of St. Peter and St. Paul, Angermiinde) by  Frederick William, Elector of Brandenburg and  Duke of Prussia.