Columbia subject headings:
Albrecht Friedrich, Duke of Prussia, 1553-1618--Correspondence--Sources.
Ermland (Ecclesiastical principality)--History--Sources--Bibliography--Catalogs.
Geheimes Staatsarchiv Preussischer Kulturbesitz--Catalogs.
Georg Friedrich, Margrave of Brandenburg-Ansbach, 1539-1603--Correspondence--Catalogs.
Reformation--Germany--Prussia--Sources--Bibliography--Catalogs.
Warmia (Poland)--History--Sources--Bibliography--Catalogs.
Harvard subject headings:
Albrecht Friedrich, Duke of Prussia, 1553-1618--Correspondence--Sources.
Ermland (Ecclesiastical principality)--History--Sources--Bibliography--Catalogs.
Ermland (Germany)--History--Sources--Bibliography--Catalogs.
Geheimes Staatsarchiv Preussischer Kulturbesitz--Catalogs.
Georg Friedrich, Margrave of Brandenburg, 1539-1603--Correspondence--Catalogs.
Georg Friedrich, Margrave von Brandenburg-Ansbach, 1539-1603--Correspondence--Catalogs.
Reformation--Germany--Prussia--Sources--Bibliography--Catalogs.
Warmia (Poland)--History--Sources--Bibliography--Catalogs.
Princeton subject headings: