Columbia subject headings:
Heads of state--Sudan--Correspondence.
Islam--Sudan--History--19th century--Sources.
Mahdī, Muḥammad Aḥmad, 1848-1885--Correspondence.
Sudan--History--1821-1881--Sources.
Harvard subject headings:
Islam--Doctrines
Islam--Sudan--Sources.
Mahdism--Sources.
Sudan--History--1821-1881--Sources.
Sudan--History--1881-1899--Sources.
Princeton subject headings: