The settlement of the Jews throughout the world is known as the Diaspora, but in fact many Jews stayed in Palestine or nearby Syria. After 638, when the Muslims conquered Jerusalem, Jews were allowed to reenter the city, and in general, they lived much better under Muslim than under Christian rule. Jews in southern Arabia fared particularly well: for many centuries, the region that is now Yemen was a wealthy community of Arab merchants who embraced the Jewish faith.
The center of Jewish life during the Middle Ages lay in Mesopotamia and Persia—modern-day Iraq and Iran. Again, the establishment of Islamic rule benefited the Jews. They had suffered some persecution under the Sas-sanid rulers of Persia, but after Muslims replaced the Sassanids in the 600s, Jews began to hold positions of influence in Persia. Jews gravitated into positions as merchants and bankers, and enjoyed considerable control over the Islamic government's purse strings. The greatest contribution of Jews in Iraq, however, was the Talmud (see box), along with other works of literature and philosophy.
North Africa represented extremes of good and bad for Jewish communities under Islam. During the late 900s in what is now Tunisia, the town of al-Qayrawan (AL ky-rah-WAHN) became the biggest center of Jewish life outside of Iraq. The experience of Jews was also relatively good in Egypt at around the same time, with the tolerant Fatimids in power; but Jewish communities there declined after the 1000s, along with the power of the Fatimids themselves. On the other hand, the rule of the Almo-hads in Morocco from the mid-1100s to the mid-1200s was particularly harsh. Jews were forcibly converted, and those who refused to accept Islam were slaughtered. As was the case in Europe at about the same time, the Al-mohads began forcing Jews to wear special clothing to set them apart from the rest of society.