'Alī ibn Mūsā al-Rezā (Arabic: علي بن موسى الرضا) also called abu al-Hasan is commonly known as Ali al-Reza (c. 29 December 765 – 23 August 818) also commonly known in Persia as Imam Reza (Persian: امام رضا), was a descendant of Prophet Muhammad and the eighth Shia Imam after his father Musa al-Kadhim and before his son Muhammad al-Jawad; and was an Imam of knowledge according to the Zaydi (Fiver) Shia school and Sufis. He lived in a period when Abbasid caliphs were facing numerous difficulties the most important of which was Shiite revolts. The Caliph Al-Ma'mun thought out a remedy for this problem by appointing Al al-Ridha as his successor, through which he could involve the Imam in worldly affairs. However, according to Shiite view, when Al-Ma'mun saw that the Imam gained even more popularity, he decided to correct his mistake by poisoning him. The Imam was buried in a village in Khorasan where afterwards gained its new name, Mashhad, the place of martyrdom.