An Imam under guard
Hasan b. Ali al-Askari (a), the eleventh Imam, was born in Madinah in 232 AH and brought as a child to Samarra, the Abbasid garrison capital, when his father Imam al-Hadi (a) was summoned there. The city's military quarter (askar) gave him his title. His six years of Imamate were spent under surveillance and periods of detention, so he dealt with his followers largely through trusted agents — among them Uthman b. Sa'id, who would become the first deputy of his son.
Martyrdom
He was poisoned in the reign of al-Mu'tamid and died on 8 Rabi al-Awwal 260 AH at the age of twenty-eight. The Abbasids searched his house for the son the Shia believed had been born to him, and interrogated the household, without result. He was buried in his own house next to his father; the two graves became the Askariyyayn shrine, whose golden dome was destroyed by bombings in 2006 and 2007 and has since been rebuilt.
Why the day matters
The eighth of Rabi al-Awwal closes the sequence of the eleven Imams' lives on earth; the following day marks the beginning of the Imamate of the twelfth, and with it the era of occultation in which the Shia still live.
Written for Shia Online Community. Dates and facts are checked against the references listed under Research & books; where the tradition records more than one date, all are given.