Columbia subject headings:
Europe--History--476-1492.
Nicephorus II Phocas, Emperor of the East, 912-969.
Otto I, Holy Roman Emperor, 912-973.
Harvard subject headings:
Europe--History--476-1492.
Nicephorus II Phocas, Emperor of the East, 912-969
Nicephorus II Phocas, Emperor of the East, 912-969.
Otto I, Holy Roman Emperor, 912-973.
Princeton subject headings: