Columbia subject headings:
Harvard subject headings:
Cities and towns, Medieval--Germany--History.
Frederick II, Holy Roman Emperor, 1194-1250.
Germany--History--Frederick II, 1215-1250.
Henry VII, Holy Roman Emperor, 1269?-1313.
Konrad IV, King of Germany, 1228-1254.
Princeton subject headings:
Cities and towns, Medieval--Germany--History.
Frederick II, Holy Roman Emperor, 1194-1250.
Germany--History--Frederick II, 1215-1250.