Columbia subject headings:
Christianity and other religions--Islam.
Christians--Islamic Empire--History--To 1500.
Islam--Relations--Christianity.
Islamic Empire--Ethnic relations--Religious aspects.
Islamic Empire--History--661-750.
Harvard subject headings:
Christians--Islamic Empire--History--To 1500.
Chtistianity and other religions--Islam--Congresses.
Islam--Relations--Christianity--Congresses
Islamic Empire--Ethnic relations--Religious aspects--Congresses.
Islamic Empire--History--661-750--Congresses.
Princeton subject headings:
Christianity and other religions--Islam--Congresses.
Islam--Relations--Christianity--Congresses.
Islamic Empire--Ethnic relations--Religious aspects--Congresses.
Islamic Empire--History--661-750--Congresses.