People have been falsely claiming to be the Mahdi since the time of the Umayyads up to the present. One of the earliest recorded false Mahdis was Salih bin Tarif, kind of Berghouata, who claimed to have a new Qur'an in the Berber language. He ordered fasting in the month of Rajab instead of the month of Ramadan and ordered 10 daily obligatory prayers instead of five, and made various other changes to religion. He and several of the more famous claimants in history are mentioned on Wikipedia.
Perhaps the most recent claimant, said to be a 36-year-old Saudi man named Sami, mounted the podium at the Haram in Mecca a few weeks ago to proclaim himself. His claim is but one of several in Mecca in the past several months. Some of the claimants have been mentally ill, and others have had political motives, but political unrest in the Arab world and the world in general certainly are associated with a rise in numbers of false Mahdis.
The Shia Hadith collections include exegesis of Qur'anic verses pertaining to the return of the real Imam Mahdi (may Allah hasten his reappearance). Verse 2:148 ("Hasten to do good works. Wherever you are, Allah will bring you all together; verily Allah has power over all things.") is said to be describing some of the events at the time of the return. In The Qa'em in the Qur'an by Sayyid Hashim Al-Bahraani (available online), some of the signs and events leading up to the return are described in detail.
Some traditions from Imam Baqir (peace be upon him) tell believers not to join any group or movement or believe in any claimant until all these signs happen within a one-year period:
- A portion of the mosque in Damascus is destroyed. The people of Syria will be divided into three groups, one of which will follow Sufyani.
- Apostate Turks march through Damascus and on to Hijaz. Greeks arrive near Tel Aviv in Ramla, and there is fighting in all Arab lands.
- A leader of one of the Syrian factions, who will be called Sufyani, will rise with a great army and will focus on killing the family of the Prophet (peace be upon him and his progeny) and their true followers. In Kufa, he will crucify and kill Shias.
- Sufyani will send soldiers to Medina hunting for the Twelfth Imam and will kill a man there, but the Twelfth Imam will remain unharmed. Part of Sufyani's army will go to Mecca, where the earth will collapse on them.
- The Twelfth Imam will pray at the Haram and will call out a passage that begins, "O people! We ask Allah to help us against those who oppressed us and usurped our rights..." (For the rest, refer to the book The Qa'em in the Qur'an.)
- 313 men and 50 women will join the Imam and his minister there without any prior appointment, from all over the world. He will get an army of ten thousand men.
- The Imam will have with him "the covenant, the flag, and the sword of the Prophet".
- A caller will call and announce the reappearance of the Twelfth Imam and will mention him by name and the name of his father and mother, and this call will be heard by everyone on Earth.
Another tradition describing the conditions in the year before the rising of Imam Mahdi is relayed via Imam Sadiq (peace be upon him) and is associated with verse 2:155 in the Qur'an. ("We shall surely try you with something of fear, and hunger, and loss of wealth, and lives, and fruits; and give glad tidings to the patient ones.") Imam Sadiq said that there will be general hunger in Syria and hunger in Kufa specific to the enemies of Ahlul Bayt, and they will starve. Syrians (people of Shaam) will be afraid of the rising of the Twelfth Imam.
These traditions usually end with a warning that others will rise with similar claims, but only the true Imam (as) will have the covenant, flag, and sword of the Prophet, and only his call will be heard everywhere on Earth. He will of course be the direct descendant of the Holy Prophet and will be recognized further by his supreme knowledge and piety inherited from his forbearers.
Even a cursory examination of people throughout history who have claimed to be the Mahdi will reveal that the conditions prior to his return and the appropriate actions, knowledge, and behavior of the real Imam have not been met. However, many people have been deceived, and more will be deceived by false claimants in the future.
People who are uneducated about true religion and the signs of reappearance, and those who fail to understand the status of Ahlul Bayt, as well as those who panic or see doomsday at every turn with impatience, are more vulnerable to misguidance than those who endure with patience, cling to the rope of guidance, and continually pursue education on these matters. In our era, an undercurrent that the time of the reappearance is drawing near has been growing. In previous eras of unrest, similar currents gained strength and then waned, but some contend this time is different. The time could be very near, or it may be that every man alive today will go to his grave before it comes. The time is not known, and anyone claiming to know the time is a liar, so we must be vigilant and look after ourselves with this understanding.