Columbia subject headings:
Emperors--Rome--Usurpation--Congresses.
Rome--Politics and government--284-476--Congresses.
Harvard subject headings:
Emperors--Rome--Usurpation--Congresses.
Rome--Politics and government--284-476--Congresses.
Princeton subject headings:
Emperors--Rome--Usurpation--Congresses.
Rome--Politics and government--284-476--Congresses.