Black Death refers to a pandemic of bubonic plague that swept Europe in the mid 14th century, killing up to half the population. The disease, carried by fleas on rats, had been around for thousands of years, and the virulence of the pandemic of 1346-1353 is ascribed to high populations living in close confines during the medieval period. But how did it get to Europe?
New research shows that it was likely related to a volcanic eruption in 1345. We don't have historical records of such an eruption, but written accounts from Europe and Asia in the years following report dark clouds and crop failures. We know this can be caused by volcanic ash circling the earth. Also, Arctic and Antarctic ice cores have dated a layer of sulphur to around 1345. Tree ring data also shows the ash clouds' effect on climate in those years. The result was that Italy had to import massive amounts of grain from Central Asia to keep the population from starving, and that's where the Black Death began to flourish. Read how a volcanic eruption somewhere in the world led to the resetting of Europe at LiveScience. -via Strange Company