Alī ibn Mūsā al-Rezā also called abu al-Hasan is commonly known as Ali al-Reza ( 29 December 765 – 23 August 818) also commonly known in Persia as Imam Reza (Persian: امام رضا), was a descendant of the Prophet Muhammad and the eighth Shia Imam after his father Musa al-Kadhim and before his son Muhammad al-Jawad. He 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 Shia revolts. The Caliph Al-Ma'mun thought out a remedy for this problem by appointing Al-Ridha as his successor, through whom he could involve the Imam in worldly affairs. However, according to the Shia 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, which afterwards gained its new name, Mashhad, meaning the place of martyrdom.