Columbia subject headings:
Rome--History--Republic, 265-30 B.C.
Harvard subject headings:
Espionage--Rome.
Intelligence service--Rome.
Rome--History--Republic, 265 B.C.-30 B.C.
Rome--History--Republic, 265-30 B.C.
Princeton subject headings:
International law--History--Rome.
Rome--History--Republic, 510-30 B.C.