This chapter shows that once the Jews became literate, urban, and engaged in skilled occupations, they began migrating within the vast territory under Muslim rule—stretching from the Iberian Peninsula to India during the eighth through the twelfth centuries, and from the Byzantine Empire to western Europe via Italy and within western Europe in the ninth through the thirteenth centuries. In early medieval Europe, the revival of trade concomitant with the Commercial Revolution and the growth of an urban and commercial economy paralleled the vast urbanization and the growth of trade that had occurred in the Umayyad and Abbasid caliphates four to five centuries earlier. The Jewish diaspora during the early Middle Ages was mainly the outcome of literate Jewish craftsmen, shopkeepers, traders, scholars, teachers, physicians, and moneylenders migrating in search of business opportunities to reap returns on their investment in literacy and education.