Father Jake had a question regarding the Mahdi and the use of the name “Mahdi Army” by Muqtada as-Sadr. He’s gone out and done a fair amount of research, and I wanted to add my two cents.
From a theological perspective, the idea of the Mahdi is incredibly ill-defined, because the idea of the end days are ill-defined in the Qur’an. While we have a sense that the mountains will crumble, stars will fall from the sky and the sky itself will tear, there is no equivalent to the Book of Revelations in the Qur’an. (For a wonderful discussion of the lyrical and symbolic presence of the akhirat, the end day, in the Qur’an, read Michael Sells, Approaching the Qur’an.)Two figures appear in almost all Muslim understandings of the end times, Dajjal, the deceiver, and the Mahdi [the Wikipedia description is not a bad bare-bones introduction], although neither appears in the Qur’an. Dajjal appears early on in Islamic eschatology, but in various forms. I can’t find evidence for him as the “anti-Christ” until several hundred years after the death of the Prophet (PBUH), but still before the colonial period. However, this is only based on a cursory search. Dajjal’s purpose is to lead all muslims (not capitalized) away from the faith. Once they have been lead astray, he will create a new world order. The vision of that order varies depending on locale and community of interpretation. The Mahdi, a common figure in both Sunni and Shiah understandings of the end days, is an equally ambiguous figure. He is seen as Hazrat Isa (Jesus), Prophet Muhammad, Prophet Khidr, for the Ithna’ashari the Hidden Imam, or in some instances, simply as a unique figure presaging the appearance of any of the above. He represents either a competing pole against Dajjal, attempting to keep muslims (no caps) with their faith(s), or as an actual physical adversary to battle Dajjal. The battle is either the Final Battle between good and evil, or the necessary triumph of good over evil before a just reign by any important religious figure (as listed above) can begin. As you can see the stories are highly amorphous, and frustrating from a theological perspective. There is a lot of theology about what happens to the individual when they die, but the last days are not part of that same spectrum. Like the qissas al-anbiya, stories of the Prophets, these stories take on a highly local flavor.
The idea of the Mahdi as a returning figure actually probably originated with Umar, who would become the second caliph, at the death of the Prophet. Umar is said to have declared that the Prophet was not dead and would in fact return. However, Abu Bakr quickly stopped the spread of that idea. With the death of Imam Jafar as-Sadiq in 765, a crisis in succession emerged in the Shi’ah community, and the nascent Ismaili community had at least five different interpretations of what the role of Imam Ismail was. Variations around the theme of a hidden Imam emerged, although back reading in history made this a period of satr, concealment, rather than ghayb, occultation; the latter is the state of the Ithna’ashari and Mustali Ismaili Imams. The Abbasids had originally wanted Imam Jafar to head their movement, and he refused. They quickly took advantage of the confusion in the Ismaili community to have some of these people join their cause and the Abbasid caliph who took control in 775 took the reignal title al-Mahdi. This ploy did work to gain some of the Ismailis over to the Abbasids, as the Abbasids claim kinship to the Prophet. However, it did not have the impact that the Abbasids had hoped.
In 909, the Fatimid state was established with the emergence of the Ismaili Imam, who took the title al-Mahdi. His goal was to unite the various Ismaili movements as the descendant of Ismail, and to herald a new world order with the formation of the Fatimid state. The Qarmatians refused to acknowledge him as the rightful descendant of the Imam Ismail, and established an oppositional identity to the Fatimid state. The title al-Mahdi was also used to reach out to the Ithna’ashari community whose Imam had gone into ghayb in 872. The theological import of the title was also used for political purposes. The Umayyad caliph in Spain, Abd ar-Rahman III, took on the the title al-Mahdi in 910 to legitimize his claim of the universal caliph of the ummah as well, and in clear opposition to the Fatimids.
The establishment of three rival claimants to the caliphate, and the settling down of Shi’ah theology precluded any claimants to the title of al-Mahdi for several hundred years. Oddly, after the Mongol eruption in the 13th century, the political situation would seem to demand the appearance of a Mahdi figure, but there is no major figure of that name during this period. In the middle colonial period, specifically the 19th century, as Father Jake points out, a Mahdist movement appears in Sudan. This movement also has heavy political overtones, but seems to have no relationship to Shi’ah understandings of the Mahdi.
In the 20th century, Ayatollah Khomeini was believed by some to have been Imam Mahdi, and to be ready to bring about the end times. It was a notion that he clearly did not dissuade.
With Muqtada as-Sadr, I don’t believe he thinks he is involved in the end days. I think he is using the title “Mahdi Army” to indicate that the “soldiers” are pure and of true intention. The eschatological imagining is not present in as-Sadr, or in his followers, conscious world-view. They do see themselves as being on a just quest, but not necessarily involved in the final battle between good and evil.