When, how, and why did the Black Death reach Europe? Historians have relied on Gabriele de’ Mussi’s account of Tatars catapulting plague-infested bodies into the besieged Genoese colony of Caffa on the Crimean Peninsula. Yet Mussi spent the 1340s as a notary in Piacenza; he had no direct knowledge of events in Caffa. Sources written by people present in the Black Sea at the time of the Second Pandemic, including Genoese colonial administrators, Venetian diplomats, Byzantine chroniclers, and Mamluk merchants, offer a different perspective on plague transmission. They show that the Venetian community at Tana played just as important a role in plague transmission as the Genoese colony at Caffa; that it took over a year (from spring 1346 to autumn 1347) for plague to cross the Black Sea to Constantinople even though that journey normally took just a few weeks; that people crossed the Black Sea in 1346 but most goods did not because of a series of trade embargoes; that grain was one of the most important Black Sea commodities in both volume and strategic value; and therefore that the embargoes of 1346 delayed plague transmission by temporarily halting the movement of grain with its accompanying rats, fleas, and bacteria. When Venice, Genoa, and the Golden Horde made peace and lifted their embargoes in 1347, the grain trade resumed and so did the spread of plague.