 His descendants further founded the Fatimid Caliphate, later called the Nizari and Mustaali.Imam Muhammad ibn Imam Ismail can be considered the first proper Ismaili Imam since Imam Isma'il ibn Ja'far predeceased his father Imam Jafar-as-Sadiq and thus he was able to act independently of previous Imams.From him came all other Ismaili Imams and subsequent sub-sects of Ismailism and it' offshoots.