This project aims to explore the implications of a neglected trade system that connected Northern Europe and the Islamic world in the 9th and 10th centuries AD. The hundreds of thousands of Islamic dirhams found in hoards strewn across Northern Europe, from England through Scandinavia to Russia, are probably a residue of a large-scale trade system. But how exactly did it operate? What commodities were traded? This project will explore the hypothesis of a massive trade in Slavic slaves, which has so far received little scholarly attention. The study of various aspects of this trade system will lead us to ask questions of fundamental importance for the study of the Middle Ages. To what extent did the unprecedented accumulation of wealth derived from the long-distance trade trigger epochal social, economic, and political change, which in turn resulted in the emergence of states in non-Carolingian Europe in the 10th century? Was slavery a central feature of some early medieval societies, the reality of which has been overshadowed by the prevalent narrative of the emergence of feudalism? Answers to these questions are of paramount importance for any study of the medieval world, and are likely to pave the way for a new vision of the emergence of Medieval Europe and of the early contacts between Europe and the Islamic World.