Columbia subject headings:
Roads--Europe--History--To 1500--Congresses.
Transportation--Europe--History--To 1500--Congresses.
Harvard subject headings:
Roads--Europe--History--To 1500--Congresses.
Transportation--Europe--History--To 1500--Congresses.
Princeton subject headings:
Roads--Europe--History--To 1500--Congresses.
Transportation--Europe--History--To 1500--Congresses.