Columbia subject headings:
Harvard subject headings:
Harbors--Western Mediterranean--History--To 1500--Congresses.
Mediterranean Region--Civilization--Congresses.
Mediterranean Region--History--To 476--Congresses.
Navigation--Western Mediterranean--History--To 1500--Congresses.
Princeton subject headings:
Harbors--Western Mediterranean Region--History--To 1500--Congresses.
Navigation--Western Mediterranean Region--History--To 1500--Congresses.