Hasan ibn Ali ibn Muhammad ( 846 – 874) was the 11th
Imam of
Twelver Shia Islam. He was also called
Abu Muhammad and
Ibn al-Ridha, and is generally known as
al-Askari (
Askar being the word for
military) for the city (
Samarra) he had to live in was a
garrison town. He was the eleventh Shia
Imam after his father
Ali al-Hadi and lived under house arrest in Samarra, especially since it was known that the Shia were looking forward to his son,
Muhammad al-Mahdi, the twelfth
Imam, who was destined to remove injustice from the world. Al-Askari married
Narjis Khatun and was kept in house arrest or prison most of his life until, according to some Shia sources, he was poisoned at the age of 28 at the instigation of the Abbasid caliph
Al-Mu'tamid and was buried in Samarra.