If there was one world-changing event that marked a break between the medieval period and the early modern period, it was the arrival of the great plague, known in Europe as the Black Death, in the middle of the fourteenth century. By the time a plague-stricken ship from the Black Sea reached Italy in 1348, the disease had already become a global pandemic. It had already caused millions of deaths in China and on the borders of Mongolia. Within a few decades, it would help bring about the collapse of the Mongol empire that had bound most of Asia together for more than a century. Over the space of a few years, the plague swept through Europe. The early Renaissance scholar and writer Giovanni Boccaccio (1313–1375) claimed to have witnessed the effects of the plague personally as it burned through Florence in 1348. Historians estimate that the plague may have caused the deaths of up to 50 percent of the population in certain areas