match in name or in his father’s name(1). This man claimed to be a descendant of Muhammad ibn Ismāīl ibn Jafar(2), and that this Maymūn was(3) Muhammad ibn Ismāīl. Those knowledgeable about genealogy, as well as other Muslim scholars, [know](4) that he lied in claiming this lineage and that his father was a Jew, the stepson of a Magian. He therefore had two affiliations: one with the Jews and one with the Magians.
He and his household were heretics, and they were the imams of the Ismailis, concerning whom the scholars said:
“Indeed(5), the outward aspect of their doctrine is Rāfidism, while its inner reality is sheer unbelief.”
The scholars composed books exposing their secrets, stripping away their veils, and demonstrating the falsity of their claims to lineage and to Islam, and showing that they had no connection to the Prophet—may Allah bless him and grant him peace—either by lineage or religion.
This Ubayd Allah ibn Maymūn, who styled himself(6) al-Mahdī, appeared in 299 AH and died in 324 AH, whereupon authority passed to