There is a book on Italian slavery called, Speaking of Slavery by Steven Epstein. For Italy, slavery would have continued into the early modern period (although there were abolitionist societies in the 19th century). The fact that Genoa and Venice were "heavily invested" in the Black Sea trade does not mean that there were excessive amounts of slaves in Italy itself. First of all, during the 13th and 14th century, the Genoese were the primary slave merchants of the period and the demand was in Egypt because the Ayyubids and later the Mamluks themselves required new slaves for each generation of soldiers as the status could not be inherited. The majority of slaves in Italy during the central Middle Ages were female domestics from eastern Europe and were rare enough to be considered status symbols.