The followers of Ahl Al-Bayt (peace be upon them) commemorate in Iraq and in the world, every year on the third of the blessed month of Rajab the sad anniversary of the martyrdom of Imam Ali Al-Hadi (peace be upon him) the tenth of our holy Imams (peace be upon them). As on the third of Rajab 254 AH the members of the Prophecy House, their lovers and followers witnessed his painful martyrdom, which was a chocking news for them, that have affected deeply Imam Al-Hassan Al-'Askari for the martyrdom of his father Imam Ali Al-Hadi (peace be upon both of them) and he was then only forty years old. Imam Al-Hassan Al-Mujtaba (peace be upon him) has said: "There is none of us (Ahl al-Bayt) except he is poisoned or killed."
Imam Ali Al-Hadi (peace be upon him) has lived in the city of his grandfather the Messenger of Allah (prayers and Allah's peace be upon him and his holy Household) for almost twenty years. Al-Mutawakkil Abbasi brought him to live in Samarra where he lived twenty years until he was killed by poison and was buried in his house where his holy shrine is now.
He (peace be upon him) spent a long period of his life in the prisons of the Abbasids. The murderer of Imam Al-Hadi (peace be upon him) was either Al-Mu'tamid Al-Abbasi as mentioned by Ibn Babawayeh, or Al-Mu'taz Al-Abbasi like stated by other historians.
On the moment of his death, a group of Bani Hashem from Talibyyin and Abbasids gathered at his house along with a great number of the Shiites, then the hallway door was opened, a black servant went out from it followed by Abu Mohammed Al-Hassan Al-'Askari (peace be upon him) without head's cover and with slotted clothes, his face looked like his father's face (peace be upon both of them). Once they have seen him like this, all those present even the children of Al-Mutawakkil, stood up.
Imam Al-'Askari (peace be upon him) sat in front of them, they kept then silent, all one could hear is only the coughs and sneezes, then a servant went out bringing the shoes of Abu Mohammed (peace be upon him) and then the funeral of Imam Al-Hadi (peace be upon him) was driven out to the street led by his son Imam Al-'Askari (peace be upon him), noting that he has prayed upon his father beforehand to bury him in his house, and all Samarra remained then in sorrows and grief.