Several years before 1999, Ahmed Alhasan joined the Hawza (in Najaf) the leading Shia Institute for religious studies in Iraq. Ahmed found that the curriculum to be disordered because the Quran and hadiths are not taught as topics. He then stayed in his house and studied alone but still kept in touch with some of the students.
In 1999 the message of Ahmed Alhasan began amongst the students of Al Hawza. He then initiated attempts at reforming the scientific, practical and financial aspects of the Hawza that were corrupted. After little response and results, in 2002 the message began to spread publicly. The message revolves around Ahmed Alhasan being a messenger of Imam Mahdi and his mission of preparing people for his appearance. Ahmed Alhasan achieves this by teaching his followers the religious beliefs, laws, divine manners, interpretations of Holy books and hadiths.
The movement started intellectually (among the students of the religious Hawza Institute) and has grown and expanded intellectually through statements and dozens of books authored by Ahmed Alhasan, as well as books written by senior members. The group has attracted followers from many countries outside of Iraq including western countries through websites in Arabic, English and other languages distributing the books and knowledge of Ahmed Alhasan. The followers of Ahmed Alhasan are called Ansar Al-Imam Al-Mahdi.
When the group grew in number, many raids were carried out against them in January 2007 including destroying mosques belonging to the Ansar in Najaf and Karbala, closing the Najaf Office, and imprisoning many Ansars simply because of their faith. The government forces carried out these raids because Iraqi Clerics urged that the call of Ahmed Alhasan be attacked. The media and journalists were prevented from reporting these events. Some reports did surface about the raids which the government had no reason to carry out. Afterwards when the Battle of Najaf in Zarka happened on 28 January 2007, government officials deliberately accused the Ansar of being involved in the battle so as to justify their previous attacks. However it was revealed that the fighting group was Soldiers of Heaven a militant shia group and their leader was Dhia Abdul Zahra Al Garawi. Later it was acknowledged that Ahmed Alhasan and Ansar Al-Imam Al-Mahdi have no connection with Soldiers of Heaven and were not involved in the Zarqa Battle of Najaf.
Additionally in December 2007 (ThulHujja 1428H) during a Najaf conference, some representatives (wakeels) of the Marje'iya clerics urged that the call of Ahmed Alhasan be fought, these words were conveyed on a Satellite TV channel. A few days later, the second Najaf Office was closed down and again many Ansars were arrested. Then after a month in January 2008 (Muharram 1429H), many Ansar were killed, imprisoned and their mosques were demolished throughout Iraq by Muqtada's forces.
Reason behind government attacks, imprisonment and media distortion:
It is worth noting a few facts to fully understand the reaction of other Iraqis towards the group which has usually been raids, killing, imprisonment and demolishing the places of worship and assembly.
Firstly, Ahmed claims to be the representative and messenger of the 12th Imam. If true, this means that he is more knowledgeable and has more authority than anyone in religious teaching and leadership which would mean the end of all taqleed following of scholars as all people would be required to follow the Yamani who is infallible. Thus this is a perceived threat to their authority over millions of followers and the huge sums of donations that they manage, so the Shia scholars would prefer to believe that the call is false than to join an emerging movement and lose their status and power.
Secondly, all the clerics are fully aware of Ahmed Alhasan because he started his message in the Hawza, the centre of Shia religious studies and the clergy. They know about the extensive knowledge of Ahmed Alhasan from his books and the proofs of his call such as the visions some people saw which made them believe. Hence the movement's power to convince people (which would reduce their taqleed followers, as has already happened) is threatening to them. As a result they have issued fatwas and statements inciting their followers and government political parties to attack the movement and the Ansar. These instigations to violence against Ansar Al-Imam AlMahdi were not hidden but many times broadcast on satellite TV channels.
Since most people and politicians in Iraq are Shia and follow a Marje' cleric, the political parties and government forces act on the clerics' wishes including their incitement to violence towards Ansar Al-Imam al-Mahdi. The government forces could not find any reason to justify their attacks and raids, so they accused the Ansar of being involved in the battle against the militant Soldiers of Heaven.
Ansar Al-Imam AlMahdi whose leader is Ahmed Alhasan have never been violent and are not affiliated with any other group. Their activities are mostly debates with other groups and Friday prayers. Despite being attacked, imprisoned and having offices and mosques destroyed (in early 2007 and 2008) they have not taken up arms to defend themselves from further government attacks.