Columbia subject headings:
Harbors--Spain--History--To 1500.
Mediterranean Region--Commerce--Spain--History--To 1500.
Portugal--Antiquities, Roman.
Spain--Antiquities, Roman.
Spain--Commerce--Mediterranean Region--History--To 1500.
Harvard subject headings:
Harbors--Italy--History--To 1500.
Harbors--Portugal--History--To 1500.
Harbors--Spain--History--To 1500.
Mediterranean Region--Commerce--Portugal.
Mediterranean Region--Commerce--Spain.
Portugal--Commerce--Mediterranean Region.
Spain--Commerce--Mediterranean Region.
Princeton subject headings: