The foremost Ismaili jurist and founder of Fatimid Ismaili jurisprudence, Abu Hanifa al-Nu‘man b. Muhammad al-Tamimi, better known as al-Qadi al-Nu‘man, was born around 290 AH/ 903 CE into a learned family in Qayrawan, in North Africa. Very little is known about his family, childhood and education. His father Abu ‘Abdullah Muhammad b. Mansur b. Ahmad b. Hayyun, was evidently a convert to Ismaili Shi‘ism from Maliki Sunnism, the prevalent Sunni school of law in Ifriqiya.
Educated as an Ismaili, in 313 AH/ 925 CE al-Nu‘man entered the service of ‘Abdullah al-Mahdi (d. 322 AH/ 934 CE), the Ismaili Imam who had founded the Fatimid caliphate in Ifriqiya in 297 AH/ 909 CE.
More at: The Institute of Ismaili Studies – Al-Nu‘man, Al-Qadi (d. 363 AH/ 974 CE).