Qadi al-Nu‘man is regarded as the founder of Fatimid historiography.
One of the greatest Ismaili jurists and theologians of the Fatimid era, Qadi al-Nu‘man was born around 903, and entered the service of the first Fatimid Caliph-Imam al-Mahdi in 925. Al-Nu‘man served the next three Fatimid Caliph-Imams in various capacities, such as the keeper of the palace library and the qadi (judge). His growing position and importance reached its zenith under the fourth Fatimid Caliph-Imam al-Mu‘izz when he became the highest judicial functionary of the Fatimid state.
Al-Nu‘man wrote over forty treatises on various subjects including law and history. One of al-Nu‘man’s principal works, the Da’a’im al-Islam (The Pillars of Islam) was composed at the request and under supervision of Fatimid Calip-Imam al-Mu’izz.
The Da’a’im, which is the main source for the study of Fatimid law, became the official legal text of the Fatimid state from the time of Imam al- Mu’izz, and it still remains the chief legal text for the Tayyibi Ismailis. The Da’a’im is divided into two volumes. The first volume deals with acts of devotion and religious duties, and the second volume deals with worldly affairs such as food, clothing, wills, inheritance, and marriage.