to Egypt, and after a stay of seven years returned home. This seems to have coincided with a kind of revival in the Isma'ilian sect, which now regarded Cairo as its headquarters. The Qarmatians had quite passed away; al-Hakim, whatever his later eccentricities, had been a patron of scholarship, the founder of an academy, the Daru l-Hikma, or "House of Wisdom," at Cairo, and had enriched it with a large library, and was himself distinguished as a student of astronomy. The reign of his grandson was the golden age of Fatimid science, and apparently Shi'ites from all parts of Asia found their way to Egypt. In 471 another da'i or missionary, Hasan-i-Sabbah, a pupil of Nasir-i-Khusraw, visited Cairo and was received by the Chief Da'i, but not allowed to see the Khalif, and eighteen months later was compelled to leave the country and return to Asia. There were two factions in Cairo, the adherents respectively of the Khalif's two sons, Nizar and Musta'li; Nasir-i-Khusraw and Hasan-i-Sabbah had already made themselves known as supporters of the elder son Nizar, but the court officials in Egypt adhered to the younger son Musta'li. When the Khalif al-Mustansir died in 487 the Isma'ilian sect divided into two new branches, the Egyptians and Africans generally recognising Musta'li, the Asiatics adhering to Nizar This latter group had already been well organised by Nasir-i-Khusraw and Hasan-i-Sabbah, who for several years previously had been preaching the rights of Nizar. On his return home, about 473, Hasan-
