The Inquisition (miḥna) of al-Maʾmūn (d. 218/833) was a serious attempt to establish the caliph as arbiter Islamic orthodoxy . It actively prosecuted by succeeding two caliphs, and finally abolished his nephew, al-Mutawakkil, in 237/852 most information we have about it far is how carried out Baghdad Various sources, mostly biographical, also tell us something its prosecution Basra, Kufa...