Map of the Muslim world. Hanbali (dark green) is the predominant Sunni school in Saudi Arabia
Ahmad ibn Hanbal, the founder of Hanbali school, was a disciple of Al-Shafi‘i. Like Shafi'i and al-Zahiri, he was deeply concerned with the extreme elasticity being deployed by many jurists of his time, who used their discretion to reinterpret the doctrines of Quran and Hadiths to suit the demands of Caliphs and wealthy. Ibn Hanbal advocated return to literal interpretation of Quran and Hadiths. Influenced by the debates of his time, he was known for rejecting religious rulings (Ijtihad) from the consensus of jurists of his time, which he considered to be speculative theology (Kalam). He associated them with the Mu'tazilis, whom he despised. Ibn Hanbal was also hostile to the discretionary principles of rulings in jurisprudence (Usul al-fiqh) mainly championed by the people of opinion, which was established by Abu Hanifa, although he did adopt al-Shafi'i's method in usul al-fiqh. He linked these discretionary principles with kalam. His guiding principle was that the Quran and Sunnah are the only proper sources of Islamic jurisprudence, and are of equal authority and should be interpreted literally in line with the Athari creed. He also believed that there can be no true consensus (Ijma) among jurists (mujtahids) of his time, and preferred the consensus of Muhammad's companions (Sahaba) and weaker hadiths. Imam Hanbal himself compiled Al-Musnad, a text with over 30,000 saying, actions and customs of Muhammad.
Ibn Hanbal never composed an actual systematic legal theory on his own, though his followers established a systemic method after his death. Much of the work of preserving the school based on Ibn Hanbal's method was laid by his student Abu Bakr al-Khallal; his documentation on the founder's views eventually reached twenty volumes. The original copy of the work, which was contained in the House of Wisdom, was burned along with many other works of literature during the Mongol siege of Baghdad. The book was only preserved in a summarized form by the Hanbali jurist al-Khiraqi, who had access to written copies of al-Khallal's book before the siege.
Relations with the Abbasid Caliphate were rocky for the Hanbalites. Led by the Hanbalite scholar Al-Hasan ibn 'Ali al-Barbahari, the school often formed mobs of followers in 10th-century Baghdad who would engage in violence against fellow Sunnis suspected of committing sins and all Shi'ites. During al-Barbahari's leadership of the school in Baghdad, shops were looted, female entertainers were attacked in the streets, popular grievances among the lower classes were agitated as a source of mobilization, and public chaos in general ensued. Their efforts would be their own undoing in 935, when a series of home invasions and mob violence on the part of al-Barbahari's followers in addition to perceived deviant views led to the Caliph Ar-Radi publicly condemning the school in its entirety and ending its official patronage by state religious bodies.