However, Ibn Taghribirdi's assertion may have alternatively been based on the fact that al-Qadi al-Numan's patronymic, "Abu Hanifah," matches with the name of the eponymous founder of the Hanafi school.
After the Fatimid conquest of Egypt and Syria, al-Nu'man left Ifriqiya and travelled to the newly founded city of Cairo, where he eventually died in 974 CE/363 AH.
[4] Under al-Mahdi began the career of Qadi al-Numan (d. 974), the founder of Ismaili law and author of its most authoritative compendium, the Kitab da'a'im al-Islam (Book of the pillars of Islam).
[5] Al-Nu'man's most prominent work, the Da'a'im al-Islam (Arabic: دعائم الاسلام "The Pillars of Islam"),[6] which took nearly thirty years to complete, is an exposition of Isma'ili jurisprudence.
[9] Another major work, the Kitab iftitah al-da‘wa wa-ibtida’ al-dawla ("The Beginning of the Mission and Establishment of the State") narrates the rise of the Fatimids.
It also discusses Abu Abdallah al-Shi'i's correspondence with the Kutama Imazighen and their military expeditions, leading to the conquest of the Aghlabids, who ruled Ifriqiya.
The book also gives an account of the circumstances leading to the revolt of al-Shi'i, for which it holds responsible the incitement of his elder brother Abu al-Abbas, and his later execution.
Ikhtilaf usul al-madhahib ("Differences Among the Schools of Law") was a refutation of Sunni principles of Islamic jurisprudence written at roughly the same time as the earliest of such works.