Hazrat Hassan bin Ali bin Muhammad (pbuh) known as Imam Hassan Askari (pbuh) is the son of Imam Hadi (pbuh), the father of Hazrat Mahdi (pbuh) and the 11th leader of Shiites. After the martyrdom of his father, he reached the Imamate at the age of 22 and was the Imamate of the Shiites for 6 years. His Imamate was under the strict control of the government of the time during the Abbasid caliphate. Finally, Imam Hasan Askari (a.s.) was poisoned and martyred on the 8th of Rabi al-Awwal 260 lunar year by the order of Motamed Abbasi and was buried in the same city of Samarra next to his father's grave.