Columbia subject headings:
Danube River Region--Antiquities, Roman--Congresses.
Excavations (Archaeology)--Danube River Region--Congresses.
Fortification--Danube River Region--Congresses.
Limes (Roman boundary)--Danube River Region--Congresses.
Rome--Boundaries--Danube River Region--Congresses.
Harvard subject headings:
Danube River Valley--Antiquities, Roman--Congresses.
Excavations (Archaeology)--Danube River Valley--Congresses.
Fortification--Danube River Valley--Congresses.
Limes (Roman boundary)--Danube River Valley--Congresses.
Romans--Danube River Valley--Congresses.
Rome--Boundaries--Danube River Valley--Congresses.
Princeton subject headings:
Danube River Region--Antiquities, Roman--Congresses.
Excavations (Archaeology)--Danube River Region--Congresses.
Fortification--Danube River Region--Congresses.
Limes (Roman boundary)--Danube River Region--Congresses.
Rome--Boundaries--Danube River Region--Congresses.