Columbia subject headings:
Authority--Religious aspects--Islam.
Authority--Religious aspects.
Authority.
Harvard subject headings:
Authority--History--Congresses.
Authority--Religious aspects--Christianity--History of doctrines--Congresses.
Authority--Religious aspects--History of doctrines--Congresses.
Authority--Religious aspects--Islam--History of doctrines--Congesses.
Authority--Religious aspects--Islam--History of doctrines--Congresses.
Middle Ages--Congresses
Political science--Byzantine Empire--History--Congresses.
Political science--Europe--History--Congresses.
Political science--Islamic countries--History--Congresses.
Social history--Medieval, 500-1500--Congresses
Princeton subject headings:
Authority--Religious aspects--Islam.
Authority--Religious aspects.
Authority.
Byzantine Empire.