Columbia subject headings:
Prussia (Germany)--Court and courtiers.
Prussia (Germany)--History.
Harvard subject headings:
Albert, Duke of Prussia, 1490-1568--Correspondence.
Elisabeth, consort of Erich I, Duke of Brunswick-Lüneburg, 1510---Correspondence.
Germany--History--1517-1648--Sources.
Nobility--Germany--Correspondence.
Princeton subject headings:
Prussia (Germany)--Court and courtiers--Correspondence.
Prussia (Germany)--History.