Columbia subject headings:
Abbasids.
Mercenary troops--Middle East.
Turkic peoples--Middle East--Politics and government.
Umayyad dynasty.
Harvard subject headings:
Abbasids.
Mercenary troops--Middle East.
Turkic peoples--Middle East--Politics and government.
Umayyad dynasty.
Princeton subject headings:
Islamic Empire--History, Military.
Turks--Islamic Empire.