Ali al-Ridha, Arabian 8th of the Twelve Imams (d. 818)
Ali ibn Musa al-Ridha (Arabic: عَلِيّ ٱبْن مُوسَىٰ ٱلرِّضَا, romanized: Alī ibn Mūsā al-Riḍā; c. 1 January 766 – 6 June 818), also spelled Rida or Reza in Persian, also known as Abu al-Hasan, was a descendant of the Islamic prophet Muhammad, and the eighth Imam in Twelver Shia Islam, 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. He is also seen as a major religious figure for many Sunnis, particularly 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 sought out a remedy for this problem by appointing Al-Ridha as his successor, through whom he could be involved 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 at the Imam Reza shrine in a city in Khorasan, which afterwards gained the name Mashhad, meaning "the place of martyrdom".