Columbia subject headings:
Epidemics--Italy--Rome--History.
Frederick I, Holy Roman Emperor, approximately 1123-1190.
Holy Roman Empire--History--Frederick I, 1152-1190.
Rome (Italy)--History--476-1420.
Harvard subject headings:
Epidemics--Italy--Rome--History.
Frederick I, Holy Roman Emperor, approximately 1123-1190.
Holy Roman Empire--History--Frederick I, 1152-1190.
Rome (Italy)--History--476-1420.
Princeton subject headings:
Epidemics--Italy--Rome--History.
Frederick I, Holy Roman Emperor, approximately 1123-1190.
Holy Roman Empire--History--Frederick I, 1152-1190.
Rome (Italy)--History--476-1420.