Columbia subject headings:
Abbasids.
Caliphs--Islamic Empire--Biography.
Hārūn al-Rashīd, Caliph, approximately 763-809.
Islamic Empire--History--750-1258.
Islamic Empire--Kings and rulers--Biography.
Harvard subject headings:
Hārūn al-Rashīd, Caliph, approximately 763-809.
Islamic Empire--Kings and rulers--Biography.
Princeton subject headings: