Islam / Sharia / Madhhab /
The Hanbali school is based upon the theories of the 9th century Islamic theologian, Ahmad Ibn Hanbal. Ahmad Ibn Hanbal never established a specific legal system, fiqh, but a system has been developed from the answers he gave his students in Baghdad.
His orientation was one in which fewer techniques were used to define laws than in the other schools. He had rejected the techniques of personal opinion, ra'y and analogy, qiyas. Instead he used the direct message from the Koran and Hadith.
Ibn Hanbal had studied with Abu Abdullah ash-Shafi'i (founder of the Shafi'i school), but deviated from his technique of human reflection in the establishment of law.
With its total reliance on finite sources, the Hanbali school has in some questions faced problems with resolving certain issues. The solution has sometimes been to use traditions generally considered to be of low reliability.
Based upon sources that are considered as divine or divinely inspired, the Hanbali school makes a claim of infallibility, and generally does not accept deviations.
The Hanbali school was popular in Iraq and Syria until the 14th century, but would suffer heavily when these lands became part of the Ottoman Empire.
Among the main contenders for Hanbali was Ibn Taymiya in the 14th century. His teachings would became central for the 18th century Wahhabi movement in Arabia, from which the state system of Saudi Arabia would develop as well modern Islamism.
The other 3 Sunni law schools were already active when the Hanbali orientation was founded. Thanks to the great fame of Ibn Hanbal, the Hanbalis were able to recruit many members from the existing schools.