Columbia subject headings:
Harvard subject headings:
Bankers--Italy--Piacenza--History--Congresses.
Economic history--Medieval, 500-1500--Congresses.
Merchants--Italy--Piacenza--History--Congresses.
Piacenza (Italy)--Commerce--History--Congresses.
Princeton subject headings:
Bankers--Italy--Piacenza--History--Congresses.
Economic history--Medieval, 500-1500--Congresses.
Merchants--Italy--Piacenza--History--Congresses.