The Black Death swept across Europe beginning in 1347, wiping out much of the population within just a few years. Historians agree the plague bacterium, Yersinia pestis, came from rodent populations in Central Asia and entered Europe through the Black Sea. But the question of why it struck with such force remains debated.
New research suggests the devastation may have begun with a volcanic eruption in 1345, triggering climate shock and famine. In response, the Italian maritime powers turned to the Mongols of the Golden Horde for grain near the Sea of Azov. That lifeline saved Italians from starvation but also carried the plague into Mediterranean ports, fueling its rapid spread across the continent.
The chain of events that unleashed the Black Death is as dramatic as it is devastating. Click through the gallery to uncover the story in full.