Al-Mahdī is a Muslim title. In Arabic the term al-mahdī (passive verbal adjective from hadā, to guide) means literally "the guided one," technically "the divinely guided one." The verb hadā with its multiderivatives, especially meaningful to desert people, is used frequently in the qur’Ān, where God is called al-Hādī ("the guiding one": 22:53; 25:33). The form mahdī, however, does not occur there.
Less than 25 years after the death of the Prophet, civil wars broke out, the Muslim community was irreparably split into two, and a dark period of perplexities and uncertainties, theological and political, set in. Among the masses of both groups—sunnites and shĪ’ite— the idea that a restorer, a renovator (mujaddid ), would come took root. The hope became personified in a future deliverer. The Sunnites, however, did not go far beyond that. Certain theologians among them included even ‘Īsa (Jesus) among the awaited restorers. When the term Mahdī was used by them, it carried no eschatological connotation. The suppressed minority, however, the Shī’ites, developed the theory that a descendant of ‘alĪ and Fāṭimah would appear in due course, fill the ungodly world with righteousness and justice, and rule for a short millennium, which would be followed by the ending of the world and final judgment. Clearly this is a reflex of Judeo–Christian messianic belief. In Shī’ite theology the creed became central. To give it sanction, a tradition was ascribed to the Prophet foretelling the advent of a descendant of his at the end of time.
The theory lent itself to imposture. Pretenders appeared from time to time. Finally the bulk of the Shī’ites, known as the Twelvers, fixed on a son of the 11th imĀm, Ḥasan al-‘Askarī, who died in 874—as the Mahdī. Not much is known about al–Mahdī other than his name Muḥammad and that he was short-lived. He disappeared mysteriously in or about 878 in a cellar at al-Ḥillah, according to some, or in a mosque at Sāmarrā, according to others. But all of the Twelvers agree that he is "the expected one"; hence, his surname al-Muntaẓar. As such he will reappear as the infallible guide and absolute ruler. Then ‘Īsa will descend and slay the false prophet (al-dajjāl, antichrist). One tradition makes ‘Īsa himself al-Mahdī.
In islam, where the admixture of religion and politics is inextricable, Mahdism has through the ages been exploited by ambitious conquerors. Noteworthy among these was ‘Ubaydullāh al-Mahdī (909–934), founder of the Fāṭimid caliphate in North Africa. The last was Muḥammad al-Mahdī of Sudan, who from 1883 to 1885 warred against Egyptian misgovernment in his country. It should also be remembered that Mahdī was used as a proper name with no eschatological connotation, one example of this use being the name of the third ‘Abbāsid caliph al-Mahdī (775–785).
Bibliography: Shorter Encyclopedia of Islam, ed. h. a. r. gibb and j. h. kramers (Leiden 1953) 310–313. ibn khaldŪn, The Muqaddimah, tr. f. rosenthal, 3 V. (New York 1958) 1: 407–408; 2:156–157, 184–186.
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