Hasan ibn Ali al-Askari (Arabic: ???????? ???? ?????? ??????????????, c.
846 – 874) was the 11th Imam of Twelver Shia Islam, after his father Ali al-Hadi.
He was also called Abu Muhammad and Ibn al-Ridha.
Because Samarra, the city where he lived, was a garrison town, he is generally known as al-Askari (Askar is the word for military in Arabic).
Al-Askari married Narjis Khatun (also recorded as Sawsan, Mariam) and was kept under house arrest or in prison for most of his life.
According to some Shia sources, he was poisoned at the age of 28 on the orders of the Abbasid caliph Al-Mu'tamid and was buried in Samarra.
It was known that many Shia were looking forward to the succession of his son, Muhammad al-Mahdi, as they believed him to be the twelfth Imam, who was destined to remove injustice from the world.