Ali b. Muhammad al-Hadi (a.s) is the tenth Shi‘a Imam. His father was Imam Muhammad b. Ali al-Jawad (a.s) and his mother was a woman named Sumanah.
He was born in the village of Sarya on the outskirts of Madinah in the month of Rajab 212/827. Historical sources describe Imam al-Hadi (a.s) as being of medium height and having a very dark complexion, similar to his father Imam al-Jawad (a.s) and grandfather Imam al-Ridha (a.s).
Imam al-Hadi (a.s) had to bear great responsibilities at a very young age due to the fact his father Imam al-Jawad (a.s) was summoned to Baghdad from Madinah when Imam al-Hadi (a.s) was no older than six years old. While his father was in Baghdad, Imam al-Hadi (a.s) took his place in Madinah, running his affairs. Less than a year later his father died, leaving him to assume the position of Imamate.
Imam al-Hadi (a.s) was a very humble man. His wealth of knowledge and great social standing increased his popularity among lay people, who believed that he truly reflected the behavior encouraged by Islam.
Al-Hasan b. AlI b. AbI Hamza narrates:
“I saw Abul Ḥasan the Third [‘Ali al-Hadī] work in the land and his feet were soaked from sweat so I asked him: May I be your ransom, where are the men? Al-Hadi replied: Oh ‘Ali, those who are better than my father and myself have laboured in their land. I asked: Who? Al-Hadi replied: The messenger of ‘Allah and the commander of the faithful and all of my forefathers laboured using their hands, as it is the work of the Prophets, Messengers, Apostles and the righteous.”
Imam al-Hadi (a.s), who lived in Madinah for most of his life, was summoned by Abbasid ruler al-Mutawakkil to the capital at the time, Samarra. Al-Mutawakkil wanted to have Imam al-Hadi (a.s) under constant monitoring as he feared that he would lead an armed rebellion against the Abbasid government. Imam al-Hadi (a.s) spent the remainder of his life in Samarra and is reported to have been poisoned by either al-Mutawakkil, or his son al-Mu‘tamid.
Imam al-Hadi (a.s) died at the age of forty in 254AH/868AD.