Muhammad Ahmad bin Abd Allah was a religious leader of the Samaniyya order in Sudan who, on June 29, 1881, proclaimed himself the Mahdi, the messianic redeemer of the Islamic faith. His proclamation came during a period of widespread resentment among the Sudanese population towards the oppressive policies of the Turco-Egyptian rulers, and capitalized on the messianic beliefs popular among the various Sudanese religious sects of the time. More broadly, the Mahdiyya, as Muhammad Ahmad's movement was called, was influenced by earlier Mahdist movements in West Africa, as well as Wahhabism and other puritanical forms of Islamic revivalism that developed in reaction to the growing military and economic dominance of the European powers throughout the 19th century. From his announcement of the Mahdiyya in June 1881 until the fall of Khartoum in January 1885, Muhammad Ahmad led a successful military campaign against the Turco-Egyptian government of the Sudan. During this period, many of the theological and political doctrines of the Mahdiyya were established and promulgated among the growing ranks of the Mahdi's supporters, the Ansars. After Muhammad Ahmad's unexpected death on 22 June 1885, a mere six months after the conquest of Khartoum, his chief deputy, Abdallahi ibn Muhammad took over the administration of the nascent Mahdist state.

https://en.wikipedia.org/wiki/Muhammad_Ahmad