Columbia subject headings:
Harvard subject headings:
Africa, North--History.
Africa, North--Kings and rulers--Biography.
Egypt--History--640-1250.
Egypt--Kings and rulers--Biography.
Fatimites.
ʻUbayd Allāh al-Mahdī, Caliph, 872 or 873-934.
Princeton subject headings:
Caliphs--Biography.
Egypt--History--640-1250.
Fatimites--Egypt--Biography.