Original sentence: Hasan died without apparent issue.Hasan's funeral was attended by many people, including the Abbasid caliph Al-Mu'tamid who is accused of being secretly responsible for the poisoning of Hasan al-Askari.However, Twelver Shi'a believe that he had one, Muhammad al-Mahdi, who was five at the time of Hasan's death and was hidden from the Abbasids.It is related in Shia sources that when Hasan's brother, Jafar ibn Ali, was getting ready to lead the funeral prayer, Hasan's son, Muhammad, approached and told him "uncle Jafar you can not lead the funeral prayer of my father because only an imam can lead the funeral prayer of another Imam".Many Sunni muslims and scholars however question the historical existence of this son.Twelver Shia believe him to be the Mahdi; a very important figure in Islamic teaching who is believed will reappear at the end of time to fill the world with justice, peace and to establish Islam as the global religion
Edited sentence: Hasan's funeral was attended by many people, including the Abbasid caliph Al-Mu'tamid who was secretly responsible for the poisoning of Hasan al-Askari.He left only one son, Muhammad al-Mahdi who was five at the time of Hasan's death (although many Sunni muslims deny his existence).It is related in Shia sources that when Hasan's brother, Jafar ibn Ali, was getting ready to lead the funeral prayer,  Hasan's son, Muhammad, approached and told him "uncle Jafar you can not lead the funeral prayer of my father because only an imam can lead the funeral prayer of another Imam".It is then reported that this boy disappeared, eluding the Abbasids who were sent to find him.The Shia believe that he, Muhammad al-Mahdi, is the Mahdi; a very important figure in Islamic teaching who is believed will reappear at the end of time to fill the world with justice, peace and to establish Islam as the global religion