An Outline of the History of Restriction on Ijtihad
-the Hanbali school, attributed to Imam Ahmad ibn Hanbal (164-241/780-855).
These four schools have survived to the present day.
[The Extinct Schools:]
The madhahib which have been abandoned are:
-The madhhab of Sufyan ibn Said al-Thawri (97-161/715-777).
-The madhhab of al-Hasan ibn Yasar al-Basri (21-110/641-728).
-The madhhab of 'Abd al-Rahman ibn 'Amr al-Awza'i (88-157/706-773).
-The madhhab of Ibn Thawr, Ibrahim ibn Khalid al-Kalbi (d. 246,/-860).
-The madhhab of Dawud ibn'Ali al-Isfahani al-Zahiri (201-270/816-883).
-The madhhab of Muhammad ibn Jarir al-Tabari (224-310/ 838-922). This madhhab was promoted by Abu Bakr ibn Abi al-Thalj (d. 325/936), and after him by his student al-Qadi al-Mu'afa ibn Zakariyya al-Nahrawani (d. 390/999).