Devout, intelligent, and an able general and administrator, the Khalifa was unable to overcome tribal dissension to unify Sudan, and was forced to employ Egyptians to provide the trained administrators and technicians he needed to maintain his self-proclaimed Islamist military dictatorship.
Background
Abdullah was born into the Ta'aisha Baqqara tribe in Darfur around 1846 and was trained and educated as a preacher and holy man. He became a follower of Mohammed Ahmed "the Mahdi" in the 1870s and was named Khalifa by the Mahdi in 1881, becoming one of his chief lieutenants.
Career
He fought at the Battle of El Obeid, where William Hicks's Anglo-Egyptian army was destroyed (November 5, 1883), and was one of the principal commanders at the siege of Khartoum, (February 1884 - January 26, 1885).
After the unexpected death of the Mahdi, Abdullah succeeded as leader of the Mahdists on the death of the Mahdi in June 1885, declaring himself "Khalifat al-Mahdi", or successor of the Mahdi.He had to suppress several revolts in 1885-1886, 1888-1889, and 1891 before emerging as sole leader.[3] At first the Mahdiyah was run on military lines as a jihad state, with the courts enforcing Sharia law and the precepts of the Mahdi, which had equal force. Later the Khalifa established a more traditional administration.