Imam Muhammad Al-Mahdi (transliterated also in Al-Mehdi)is the twelfthImam for the Shiite Muslims (Twelvers). He was born on 15 Sha‘ban 255 AH (≈29July869) in the city of Samarra. His father is ImamAl-Hasan ben Ali ben Muhammad(Imam Al-Hasan Al-Askari) and his mother isNarjis (who was originally the Byzantine Empire). His teknonymic (Kunya) is Abo Salih and his title is Al-Mahdi (the guided one).
Imam Al-Mahdi’s birth has been surrounded by secrecy because his life was in danger from the then Abbasid governors. When his father Imam Al-Askari passed away, the then Muslims and the followers recognised that Imam Al-Mahdi is the successor Imam. Shortly after the death of his father, Imam Al-Mahdi’s occultation started. However, this occultation is divided into two periods: smaller and greater occultation. The smaller occultation started in 260 AH (874) and ended after 72 years. During that period, Imam Al-Mahdi appointed four deputies to contact his followers through these mediators. They were: Othman ben Saed Al-Omari, Muhammad ben Othman Al-Omari, Al-Hussein ben Roh An-Nawbakhti and Ali ben Muhammad As-Samri.
By the death of the fourth deputy in 329 AH (941), and as Imam Al-Mahdi noted in a letter to his last deputy, the greater occultation started.
According to the Shiite Muslims (Twelvers), Prophet Muhammad (Peace be Upon Him and His Family) noted to Imam Al-Mahdi in his Hadith and pointed that this Imam will appear after the tyranny, corruption and oppression prevail in the globe. Thus, Imam Al-Mahdi will appear to prevail justice and peace and to take humanity to the safe seashore.