Columbia subject headings:
Aachen (Germany)--History.
Holy Roman Empire--History--1517-1648.
Holy Roman Empire--Politics and government.
Reformation--Germany--Aachen.
Harvard subject headings:
Aachen (Germany)--History.
Church and state--Germany--Aachen.
Rudolf II, Holy Roman Emperor, 1552-1612.
Princeton subject headings:
Aachen (Germany)--History.
Germany--History--1517-1648.