A This chapter builds on recent scholarship to assert that the Greater Mediterranean region has been host to large-scale, multicultural, and multi-ethnic slave systems, without a break, from ancient times through the twentieth century. This chapter provides the contours of these systems for the medieval millennium, with a focus on the emergence of ‘Renaissance’ slavery in later medieval southern Europe. It then covers the major theoretical models which have been posited regarding medieval Mediterranean slavery, from Verlinden and Braudel, to Abu-Lughod, Horden and Purcell, Michael McCormick, and Alice Rio. Finally, the chapter addresses some insights which the study of a millennium of slavery in the Mediterranean can have for historians of the Atlantic Slave Trade and other more recent forms of slavery. For example, to what extent was race a determinant of enslaveability in the medieval period? How did religion inform enslaveability in the long run? Why did much of Western Europe prove resistant to slavery after the year 1100? And how did ‘Renaissance’ slavery set the stage for the creation of the Atlantic Slave System, a system already underway with the lucrative exploitation of the Canary Islands from the 1340s?