I have a hunch.
ping.
Thousand+ years ago. The al-Mahdi is suppose to be the 12th Imam, coming to the Muslims before the end of the world.
These are some of the characteristics of the awaited one.
http://www.mahdiwatch.org has a lot of information. It is the website where I found the translation of O Ba Ma in Persian = he is with us.
The prophecies about the Dajjal and the Mahdi are from Muhammad -- they just are not in the Qur'an. They are in the Hadith.
For Muslims, the Qur'an is the words spoken by Allah himself through the angel Gabriel to Muhammad, and the Hadith are the words of Muhammad himself. They were compiled after Muhammad had died from oral stories by family, friends, acquaintances and bystanders -- sometimes hundreds of years after Muhammad's death. There are hundreds of thousands of these anecdotal stories. Some of them are actually quite scandalous; hence Muslim "scholars" have carefully sifted through them and declare them as "reliable," "unreliable," or indetermined. And each scholar has his own list.
The Qur'an talks a lot about the Day of Judgment (Qiyamah), but you have to go to the Hadith to read about the details of the events leading up to the Last Day.
Much of it is plagiarized from Biblical prophecy or Middle East traditions, but all of it gets painted with the brush of Muslim jihadist violence.
End-Time Prophecies in the Hadith
from the Univ. of Southern California / Muslim Students Assoc. Hadith Database
[n.b. a lot of typos]
Hadith Collection of Sahih Muslim
Book 41: The Book Pertaining to the Turmoil and Portents of the Last Hour (Kitab Al-Fitan wa Ashrat As-Sa`ah)
description of the Major and Minor Signs of Qiyama, including the Dajjal
Hadith Collection of Sahih Bukhari
Book 88: Afflictions and the End of the World
description of the Major and Minor Signs of Qiyama, including the Dajjal
Hadith Collection of Sunan Abu-Dawud
Book 36: The Promised Deliverer (Kitab Al-Mahdi)
description of the Mahdi
Hadith Collection of Sahih Bukhari
Book 30: Virtues of Madinah
tells how the Dajjal cannot enter Medina or Mecca