Columbia subject headings:
Christianity and other religions--Islam--History--To 1500.
Church history--Middle Ages, 600-1500.
Islam--Relations--Christianity--History--To 1500.
Harvard subject headings:
Christianity and other religions--Islam--History--To 1500.
Church history--Middle Ages, 600-1500
Islam--Relations--Christianity--History--To 1500.
Princeton subject headings:
Christianity and other religions--Islam--History--To 1500.
Church history--Middle Ages, 600-1500.
Islam--Relations--Christianity--History--To 1500.