Ma'mun, Al-

At the beginning of 833 al-Ma'mun decided to require adherence to Mu'tazilah from all his subjects. As the caliph was then on an expedition against the Byzantines in the region of Tarsus, he entrusted this task to his representative in Baghdad, the prefect of police Ishaq ibn Ibrahim. The latter first called together the qadis (judges) to urge them to recognize the Mu'tazili doctrine;