In 1346, spread by infected galleys coming from Kaffa (Crimea), the Black Death reached Genoa, as it now seems, in the late summer of 1347 AD. Genoa functioned as an epicentre from which the contagion was spread into the mainland through a complex system of routes, which linked Liguria to northern and central Italy.

Fleas riding on black rats in the holds of Italian ships bring the bacterium Yersina pestis (Yp)to the port cities. Yp was the cause the Black Plague, which will kill 25 million Europeans – a third of the population – by 1351.