Columbia subject headings:
Frederick I, Holy Roman Emperor, approximately 1123-1190.
Germany--History--Frederick I, 1152-1190.
Harvard subject headings:
Frederick I, Holy Roman Emperor, approximately 1123-1190.
Germany--History--Frederick I, 1152-1190.
Holy Roman Empire--Kings and rulers--Biography.
Princeton subject headings:
Frederick I, Holy Roman Emperor, approximately 1123-1190.
Germany--History--Frederick I, 1152-1190.