Columbia subject headings:
Harvard subject headings:
Civilization, Ancient--Congresses
Communication in politics--Greece--Congresses.
Communication in politics--History--To 1500--Congresses.
Communication in politics--Rome--Congresses.
Public opinion--Greece--Congresses.
Public opinion--History--To 1500--Congresses.
Public opinion--Rome--Congresses.
Princeton subject headings:
Communication--Social aspects--History--Congresses.
Propaganda--History--Congresses.
Public opinion--History--Congresses.