Columbia subject headings:
Architecture, Domestic--Rome--Congresses.
Palaces--Rome--Congresses.
Harvard subject headings:
Architecture, Roman--Congresses.
Palaces--Rome--Congresses.
Palaces--Rome--History--Congresses.
Rome--History--Lucius Septimius Severus, 193-211--Congresses.
Severus, Lucius Septimius, Emperor of Rome, 146-211--Congresses.
Princeton subject headings:
Architecture, Domestic--Rome--Congresses.
Palaces--Rome--Congresses.