An Analysis on al-Mamun's Insist and Imam Reza's Denial over the Issue of Succession to Caliphate

The issue of Imam Reza's succession to Caliphate in Abbasid Court was the most important political matter ever happened during the political history of the Imams. Al-Mamun offered the caliphate seat, for which his ancestors fought and struggled for many years and he willingly killed his own brother to have, to his family's rival through insist and threats and without any price to pay. Despite his ancestor's legitimate struggle to take back this seat, Imam Reza refused to accept the succession This event brought up different assumptions for many researchers. With a political hypothesis and exploring some opinions that attribute Mutazilites or Shiite notions to al-Mamun, an with a brief eye on the issue of Imamate from the Shiite and Mutazilites points of view, this paper examines the succession issue outside the boundaries of political motivations and introduces the religious beliefs of the both parties involved as well as their political stands as effective factors in their insists and denials over the issue.