Mutazilite theology moved from academic debate to state policy under the Abbasid caliph al Mamun, who in 833 launched an inquisition known as the mihna requiring scholars and officials to publicly affirm doctrines associated with Mutazilite rationalism, most prominently that the Quran was created rather than eternal, a position closely bound up with the school's wider rejection of eternal realities existing alongside God's essence, since an eternal, uncreated Quran would itself constitute exactly the kind of second eternal thing the doctrine of divine unity without eternal attributes was meant to rule out. Ahmad ibn Hanbal's public refusal to affirm the doctrine, and his imprisonment for that refusal under al Mamun's two successors, made him a symbol of traditionalist resistance to state enforced rationalist theology, and Marshall Hodgson's history describes the mihna's ultimate failure, formally ended by caliph al Mutawakkil in 848, as a turning point after which Mutazilite theology lost official patronage across most of the Sunni world even as it continued to shape later Twelver Shia and Zaydi theological method, both of which retained versions of the Mutazilite position on divine attributes and unity long after Sunni orthodoxy had settled decisively with the rival Ash'ari school.