Ahmad ibn Hanbal
He released from prison the famous jurist Ahmad ibn Hanbal ibn Hilal ibn Asad al-Shaybani, who opposed the Mutazilites in their opinion that the Quran was created. Ahmad ibn Hanbal, the founder of the Hanbali madhhab, was arrested and tortured throughout the reigns of, respectively, al-Ma'mun (813-833), his brother and al-Mutawakkil's father, al-Mutassim, and his son al-Wathiq.