Muhammad ibn Hasan al-Mahdī (
Arabic: محمد بن الحسن المهدي) is believed by
Twelver Shī‘a Muslims to be the
Mahdī, an ultimate savior of humankind and the final
Imām of
the Twelve Imams who will emerge with
Isa (Jesus Christ) in order to fulfill their mission of bringing peace and justice to the world. Twelver Shī‘a believe that al-Mahdī was born in 869 (15
Sha‘bān 255 AH) and assumed
Imamate at 5 years of age following the death of his father
Hasan al-Askari. In the early years of his
Imamate he would only contact his followers through
The Four Deputies. After a 72-year period, known as
Minor Occultation, a few days before the death of his fourth deputy
Abul Hasan Ali ibn Muhammad al-Samarri in 941, he is believed to have sent his followers a letter. In that letter that was transmitted by al-Samarri he declared the beginning of
Major Occultation during which Mahdi is not in contact with his followers.