Muhammad al-Mahdi

Hujjat Allah ibn al-Hasan al-Mahdi is believed by the Twelver Shia to be the Mahdi, an eschatological redeemer of Islam and the final Imam of the Twelve Imams who will emerge with Isa (Jesus) in order to fulfil their mission of bringing peace and justice to the world. Twelver Shias believe that al-Mahdi was born on the 15th Sha'ban 870 CE/ 256 AH and assumed Imamate at nearly four years of age following the killing of his father Hasan al-Askari. In the early years of his Imamah, he is believed to have had contact with his followers only through The Four Deputies. This period was known as the Minor Occultation and lasted from 873–941 CE. A few days before the death of his fourth deputy Abu al-Hasan Ali ibn Muhammad al-Samarri in 941, he is believed to have sent his followers a letter. In that letter, which was transmitted by al-Samarri, he declared the beginning of Major Occultation, during which Mahdi was not to be in contact with his followers directly, but had instructed them to follow the pious high clerics for whom he has mentioned some distinguishing merits.