During the reign of al-Maʾmūn (813–833) the implications of all this ʿilm-based activity for caliphal authority began to become clear. Al-Maʾmūn came to the caliphate as the result of the fourth fitnah, which reflected the persisting alienation of Khorāsān. Al-Maʾmūn’s father, Hārūn al-Rashīd, provided for the empire to be divided at his death between two sons. Al-Amīn would rule in the capital and all the western domains, and al-Maʾmūn, from his provincial seat at Merv in Khorāsān, would rule the less significant east. When Hārūn died, his sons struggled to expand their control. Al-Maʾmūn won. During his reign, which probably ...(100 of 41057 words)