Columbia subject headings:
Harvard subject headings:
Celtic Church--History
Christianity and other religions--Celtic
Ireland--Church history--To 1172.
Missions--Europe, Central.
Missions--Slaves.
Missions--Slavs.
Slavic countries--Civilization.
Princeton subject headings:
Celtic Church--History.
Christianity and other religions--Celtic.
Ireland--Church history--To 1172.
Missions--Central Europe.
Missions--Slaves.
Slavic countries--Civilization.