any of the Islāmic courts of inquiry established about AD 833 by the ʿAbbāsid caliph al-Maʾmūn (Maʾmūn, al-) (reigned 813–833) to impose the Muʿtazilite doctrine of a created Qurʾān (Islāmic sacred scripture) on his subjects.

The Muʿtazilites, a Muslim theological sect influenced by the rationalist methods of Hellenistic philosophy, taught that God was an absolute unity admitting of no parts. This rationale was brought to bear on the problem of God's Word, the Qurʾān: because the Word is God and not a part of Him, the Qurʾān, as a verbal expression and thus a material thing removed from God, had to be created by God in order to be accessible to man. In contrast, the traditionalist view held that the Qurʾān was uncreated and external, essentially, that it had existed along with God since the beginning of time.

Al-Maʾmūn adopted the Muʿtazilite view and demanded that all judges and legal scholars in the empire submit to questioning to determine the soundness of their positions. Most acquiesced, utilizing the principle of taqiya (concealment of one's beliefs under duress) to avoid imprisonment. When al-Maʾmūn died, the new caliph, al-Muʿtaṣim (Muʿtaṣim, al-) (reigned 833–842), continued the policies of his brother. The caliph al-Wāthiq (reigned 842–847) also vigorously enforced the miḥnah, in one case trying himself to execute a man he considered a heretic. The inquisition continued until about 848, when al-Mutawakkil (Mutawakkil, al-) (reigned 847–861) made the profession of the Muʿtazilite view of a created Qurʾān punishable by death. See also Muʿtazilah.