imam Jafar al-Sadiq had a son named ismail who was the oldest of his children. Ismail died during the lifetime of his father who summoned witness to his death, including the g
…overnor of Medina . concerning this question some believed that Ismail did not die but went into occultation , that he would appear again and would be the promised Mahdi. they further believed that the summoning of witness on the part of the imam for Ismail was a way of hiding the truth in fear of Mansur , the Abbasid caliph. another group believed that the true Imam was Ismail whose death meant the imamate was transferred to his son Muhammad. A third group also held that although he died during the lifetime of his father, he was the imam and that the imamate passed after him to Muhammed ibn Ismail and his descendants. the first two groups soon became extinct, while the third branch continues to exist to this day and has undergone a certain amount division. the Ismailis have a philosophy in many ways similar to that of the Sabaeans (star worshippers ) combined with elemnts of Hindu Gnosis . in the sciences and decrees of islam, they believe that each exterior reality(Zahir) has an inner aspect(Batin) and each element of revelation(tanzil) a hermeneutic and esoteric exegesis. the Ismailis believe that the earth can never exist without a proof(Hujjah) of god. the proof is of two kind:speaker(Natiq) and silent one(samit).the speaker is a prophet and the silent on is an imam or Guardian(Wali) who is the inheritor or the executor of the testament(wasi) of the prophet. in ny case, the proof of GOD is the perfect theophany of the divinity. the principle of the proof of God revolves constantly around the nubmer seven.A prophet,who is sent by God,has the function of prophecy,of bringing a Divine Law or Shariah .A prophet ,who is the perfect manifestation of God, has the esoteric power of initiating men into the Divine Mysteries(wilayah). After him, there are seven executors of his testament (wasi) who possess the power of executing his testament And the power of esoteric initiation into the Divine Mysteries. the seventh in the succession possesses those two powers and also the additional power of prophecy. the cycle of seven executors is then repeated with the seventh a prophet. the Ismailis says that Adam was sent as a prophet with the prophecy and of esoteric guidace and he had seven executors of whom the seventh was Noah,who had three function of nabuwwah, wisayah and wilayah . Abraham was the seventh executor of Noah, Moses the seven executor of the Abraham, Jesus the seventh executor of the Moses, Muhammad the seventh executor of Jesus and muhammad ibn ismail the seven executor of the muhammad. they consider the wasis of the prophet to be:Ali,Husayn ibn Ali(they do not consider Imam Hasan among the imams),ALi ibn Husayn al-sajjad,Muhammad al-Baqir, Jafar al Sadiq, Ismail ibn Jafar and muhammed ibn ismail.after this series there are seven descendants of muhammad ibn ismail whose names are hidden and secert.fter them, there are the first seven rulers of the fatimid caliphate of Egypt the first of whom,Ubaydullah Al Mahdi, was the founder of the fatimid dynasty.the Ismailis also believe that in adition to the proof of GOd there are always present on earth the twelve chiefs (naqib) who are the companions and elite followers of the Proof. some of the branches of BAtinis,however, like Druzes, believe six of the chiefs to be from the Imams and six fr6m others. ( Full Answer )