Before the trade in slaves shifted to the Atlantic Ocean at the end of the ﬁfteenth century, merchants from Genoa, Venice, Palermo, and other Italian cities, supplied Muslim and Christian markets with slaves captured in lands outside of the Roman communion. Although Italians did not engage in slave trading with quite the same dedication that Catalan and Portuguese merchants applied to the business in the fourteenth and ﬁfteenth centuries, the Genoese and the Venetians nevertheless offered them stiff competition. The demise of the Roman Empire in the West and thechanges in land tenure in the early Middle Ages contributed to a marked decline in slavery in Italy, but not its extinction. Venetians, for one, were supplying Muslims with slaves from Europe as early as the eighth century.Trading in and owning slaves increased after the ports of the eastern Mediterranean became accessible to Italian merchants at the start of the thirteenth century, but the most intense periodof Italian involvement in slave trading occurred during the 100 years before the most proﬁtable trade shifted to the Atlantic Ocean in the late ﬁfteenth century.Merchants from Italy acquired slaves mainly in the markets of the eastern Mediterranean and the Black Sea and, to a lesser extent, by raiding unprotected coastlines.
After the fall of the Byzantine Empire in 1204 and the establishment of the Latin principalities in what is today mainland Greece and in the Aegean Islands, Venice, Genoa and independent Catalan adventurers vied with the Turkish emirates of Asia Minor for dominance over the region. Traders stripped the dismembered Byzantine Empire of much of its human ﬂesh. Until the late ﬁfteenth century, slave auctions in Black Sea ports and throughout the Aegean took place at the end of summer. Merchants came tothe ports of Caffa and Tana in the Black Sea mainly in search of grain, furs, cow hides,wax, honey, salt and of course ﬁsh, which they exported to Italy, but slaves ﬁgured pro-minently among their cargoes.
Thebes and the main port on the island of Negroponte (modern Euboia) also drew Christian and non-Christian traders in search of slaves. The slaves came from the hinterlands of the ports and from the islands and coast-lines all around the eastern Mediterranean and Black Sea. They were brought tomarket by local traders who sold them to the Christians and Muslims who hadcome there in search of good deals and marketable goods. No description of the markets or the condition of slaves put up for sale in those ports survives, but the methods of their conﬁnement were very likely to have changed little since the ninth and tenth centuries, when travellers described seeing bands of young men and women, often shackled around the neck or legs, herded together on shorelines,waiting to be loaded on to vessels.
By the fourteenth century, transporting slaves by sea presented problems that Venice sought to minimise by prohibiting the transport of slaves on galleys.
Merchants could contain the threat of slave revolt or panic more easily on cogs or other round ships than on narrow and low-laying galleys. Unlike galleys with their limited and unsuitable cargo space, the cogs adapted for use in Mediterranean water had holds in which groups of slaves could be stowed more securely than was possible in oar-propelled galleys