Columbia subject headings:
Harvard subject headings:
Frederick I, Holy Roman Emperor, approximately 1123-1190.
Otto I, Bishop of Freising, -1158. Gesta Friderici I. Imperatoris.
Princeton subject headings:
Frederick I, Holy Roman Emperor, approximately 1123-1190.
Germany--History--Frederick I, 1152-1190.
Otto, Bishop of Freising, d.1158. Gesta Friderici I. Imperatoris.