to the Jewish Banu Janba in 630 is said by Al-Baladhuri to have been seen in Egypt. A copy, written in Hebrew characters, has been found in the Cairo Geniza. Many Jewish residents had no reason to feel kindly toward the former masters of Egypt. In 629 the Emperor Heraclius I had driven the Jewish population from Jerusalem, and this was followed by massacres of Jewish residents throughout the empire—in Egypt, often aided by the Coptic population, who may have been trying to settle old grievances against Jewish groups, dating from the Persian conquest of Amida at the time of Emperor Anastasius I (502) and of Alexandria by the Persian general Shahin Vahmanzadegan (617), when some of the Jewish residents sided with the conquerors. The Treaty of Alexandria (November 8, 641), which sealed the Arab conquest of Egypt, expressly stipulated that the Jewish residents were to be allowed to remain in that city unmolested; and at the time of the capture of that city, 'Amr ibn al-'As, in his letter to the caliph, relates that he found there 40,000 Jews. Of the fortunes of the Jewish population of Egypt under the Umayyad and Abbasid Caliphates (641–868), little is known. Under the Tulunids (863-905), the Karaite community enjoyed robust growth. Rule of the Fatimid Caliphs (969 to 1169) At this time, Jews from North Africa came to settle in Egypt after the Fatimid conquest of Egypt in 969. These Jewish immigrants made up a significant amount of the population from all the Jews living in Egypt. Due to the discovery of the Cairo Geniza documents at the end of the 19th century, a lot is known about Egyptian Jews. From private records, letters, public records, and documents, these sources held the information about the society of the Egyptian Jews. The rule of the Fatimid Caliphate was in general favorable for the Jewish communities, except the latter portion of al-Hakim bi-Amr Allah's reign. The foundation of Talmudic schools in Egypt is usually placed at this period. One of the Jewish citizens who rose to high position in that society was Ya'qub ibn Killis. The caliph al-Hakim (996–1020) vigorously applied the Pact of Umar, and compelled the Jewish residents to wear bells and to carry in public the wooden image of a calf. A street in the city, al-Jawdariyyah, was designated for Jewish residency. Al-Hakim, hearing allegations that some mocked him in verses,