Columbia subject headings:
Harvard subject headings:
Rome--History--Empire, 30 B.C.-476 A.D.
Rome--Politics and government--30 B.C.-476 A.D.
Princeton subject headings:
Emperors--Rome.
Italy--History--To 476.
Rome--History--Empire, 30 B.C.-476 A.D.
Rome--Politics and government--30 B.C.-476 A.D.