Columbia subject headings:
Byzantine Empire--Foreign relations--Islamic Empire.
Christianity and other religions--Islam--History--To 1500.
Islam--Relations--Christianity--History--To 1500.
Islamic Empire--Foreign relations--Byzantine Empire.
Religion and international relations--History--To 1500.
Harvard subject headings:
Byzantine Empire--Foreign relations--Islamic Empire.
Christianity and other religions--Islam--History--To 1500.
Islam--Relations--Christianity--History--To 1500.
Islamic Empire--Foreign relations--Byzantine Empire.
Religion and international relations--History--To 1500.
Princeton subject headings:
Byzantine Empire--Foreign relations--Islamic Empire.
Christianity and other religions--Islam--History--To 1500.
Islam--Relations--Christianity--History--To 1500.
Islamic Empire--Foreign relations--Byzantine Empire.
Religion and international relations--History--To 1500.