Columbia subject headings:
Caliphate--History.
Caliphs--Biography.
Islamic Empire--History.
Muḥammad, Prophet, -632--Biography.
Harvard subject headings:
Caliphate--History
Caliphs--Biography.
Islamic Empire--History.
Muḥammad, Prophet, -632--Biography.
Princeton subject headings:
Caliphate--History.
Caliphs--Biography.
Islamic Empire--History.
Muḥammad, Prophet, -632--Biography.