small numbers: during the early Byzantine 6th century there were 43 communities; during the Islamic period and the intervening Crusades there were 50 (including Jerusalem, Tiberias, Ramleh, Ashkelon, Caesarea, and Gaza); and during the early Ottoman 14th century there were 30 (including Haifa, Shechem, Hebron, Ramleh, Jaffa, Gaza, Jerusalem, and Safed). The majority of the Jewish population during the High Middle Ages lived in Iberia (what is now Spain and Portugal) and in the region of Mesopotamia and Persia (what is now Iraq and Iran), the former known as the Sefardim and the latter known as the Mizrahim. A substantial population existed also in central Europe, the so-called Ashkenazim. Following the expulsion of Sephardim from Iberia during the 15th century, a mass migration into the Ottoman Empire swelled the size of many eastern communities including those in Palestine; the town of Safed reached 30,000 Jews by end of the 16th century. The 16th century saw many Ashkenazi Kabbalists drawn to the mystical aura and teachings of the Jewish holy city. Johnson notes that in the Arab-Muslim territories, which included most of Spain, all of North Africa, and the Near East south of Anatolia in the Middle Ages, the Jewish condition was easier as a rule, than it was in Europe. Over the centuries following the Crusades and Inquisition, Jews from around the world began emigrating in increasing numbers. Upon arrival, these Jews adopted the customs of the Mizrahi and Sephardi communities into which they moved. Diaspora Following the failure of the second revolt against the Romans and the exile, Jewish communities could be found in nearly every notable center throughout the Roman Empire, as well as scattered communities found in centers beyond the Empire's borders in northern Europe, in eastern Europe, in southwestern Asia, and in Africa. Farther to the east along trade routes, Jewish communities could be found throughout Persia and in empires even farther east including in India and China. In the Early Middle Ages of the 6th to 11th centuries, the Radhanites traded along the overland routes between Europe and Asia earlier established by the Romans, dominated trade between the Christian and the Islamic worlds, and used a trade network that covered most areas of Jewish settlement. In the middle Byzantine period, the khan of Khazaria in the northern Caucasus and his court converted to Judaism, partly in order to maintain neutrality between Christian Byzantium and the