Columbia subject headings:
Customary law, International--History.
International law--History.
Law, Greek.
Roman law.
Harvard subject headings:
Greece--Foreign relations.
International law (Greek law)
International law (Greek law)--History.
International law (Roman law)--History.
International law--(Roman law)
International law--History.
Rome--Foreign relations.
Princeton subject headings:
Greece--Foreign relations.
International law and relations--History.
Rome--Foreign relations.