Columbia subject headings:
Germany--History--Frederick II, 1215-1250.
Heinrich VII, King of Germany, 1211-1242.
Holy Roman Empire--History--Frederick II, 1215-1250.
Harvard subject headings:
Germany--History--843-1273.
Germany--History--Frederick II, 1215-1250.
Heinrich VII, King of Germany, 1211-1242.
Holy Roman Empire--History--Frederick II, 1215-1250.
Princeton subject headings: