Columbia subject headings:
Harvard subject headings:
Civilization, Medieval--13th century
Frederick II, Holy Roman Emperor, 1194-1250.
Germany--History--Frederick II, 1215-1250.
Germany--Kings and rulers--Biography.
Holy Roman Empire--History--Frederick II, 1215-1250.
Holy Roman Empire--Kings and rulers--Biography.
Princeton subject headings:
Frederick II, Holy Roman Emperor, 1194-1250.
Holy Roman Empire--History--Frederick II, 1215-1250.
Holy Roman Empire--Kings and rulers--Biography.