Sudan: The Tomb of the Mahdi, Omdurman, Khartoum. Photo by Petr Adam Dohnalek (CC BY-SA 3.0 License). Muhammad Ahmad bin Abd Allah (12 August 1844 - 22 June 1885) was a religious leader of the Samaniyya order in Sudan who, on June 29, 1881, proclaimed himself as the Mahdi or messianic redeemer of the Islamic faith. His proclamation came during a period of widespread resentment among the Sudanese population of the oppressive policies of the Turco-Egyptian rulers, and capitalised on the messianic beliefs popular among the various Sudanese religious sects of the time.