Concerning this question , some believed that Isma’il 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 witnesses on the part of the Imam for Isma’il’s death was a way of hiding the truth in fear of al-Mansur, the Abbasid caliph. Another group believed that the true Imam was Isma’il 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 Muhammad ibn Isma’il 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 of division.
The Isma’ilis have a philosophy in many ways similar to that of the Sabaeans (star worshippers). combined with elements 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 (ta’wil). The Isma’ilis believe that the earth can never exist without Proof (hujjah) of God. The Proof is two kinds: "speaker" (natiq) and "silent one" (samit). The speaker is a prophet and the silent one is an Imam or Guardian (wali) who is the inheritor, or executor of the testament (wasi) of a prophet. In any case the Proof of God is the perfect theophany of the Divinity.
The principle of the Proof of God revolves constantly around the number seven. A prophet (nabi), who is sent by God, has the function of prophecy (nubuwwat), of bringing a Divine Law or Shari’ah. A prophet, who is the perfect manifestation of God, has the esoteric power of initiating men into the divine Mysteries (walayat). After him there are seven of his testament (wasi) who possess the power of executors of his testament (wasayat) and the power of esoteric initiation into the Divine Mysteries (walayat). The seventh in the succession possesses those two powers and also the additional power of prophecy (nubuwwat). The cycle of seven executors (wasis) is then repeated with the seventh a prophet.
The Isma’ilis say that Adam was sent as a prophet with the power of prophecy and of esoteric guidance and he had seven executors of whom the seventh was Noah, who had the three functions of nubuwwat, wasayat, and walayat. Abraham was the seventh executor (wasi) of Noah, Moses the seventh executor of Abraham, Jesus the seventh executor of Moses, Muhammad the seventh executor of Jesus, and Muhammad ibn Isma’il the seventh executor of 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, Ja’far al-Sadiq, Isma’il ibn Ja’far, and Muhammad ibn Isma’il. After this series there are seven descendants of Muhammad ibn Isma’il whose names are hidden and secret. After them there are the first seven rulers of the Fatimid caliphate of Egypt the first of whom, ’Ubaydallah al-Mahdi, was the founder of the Fatimid dynasty. The Isma’ilis also believe that in addition to the Proof of God there are always present on earth twelve "chiefs" (naqib) who are the companions and elite followers of the Proof. Some of the branches of the Batinis, however, like the Druzes, believe six of the "chiefs" to be from the Imams and six from others.
Shia Divisions: Zaydism and Its Branches
