Columbia subject headings:
Harvard subject headings:
Ireland--Relations--Scandinavia--Congresses.
Irish Sea Region--History--To 1500--Congresses.
Scandinavia--Relations--Ireland--Congresses.
Vikings--Ireland--Congresses.
Vikings--Irish Sea Region--Congresses.
Princeton subject headings:
Ireland--Relations--Scandinavia--Congresses.
Irish Sea Region--History--To 1500--Congresses.
Scandinavia--Relations--Ireland--Congresses.
Vikings--Ireland--Congresses.
Vikings--Irish Sea Region--Congresses.