Columbia subject headings:
Commerce--History--To 1500.
Commerce--Social aspects--Europe--History--To 1500.
Harvard subject headings:
Commerce--History--To 1500.
Commerce--Social aspects--Europe--History--To 1500.
Europe--Commerce--History--To 1500.
Princeton subject headings:
Contracts--Europe--History--To 1500--Congresses.
Juristic acts--Social aspects--Europe--Congresses.
Negotiation--Europe--History--To 1500--Congresses.