In 1347, ships arrived in Sicily with a terrifying secret in their cargo: a deadly disease that would soon be called the Black Death. Within four years, it swept across Europe and killed an estimated 25 million people - roughly a third of the entire population of the continent.
The disease was bubonic plague, caused by a bacterium called Yersinia pestis. It traveled in the fleas that lived on black rats, and black rats traveled wherever ships and grain went. Once it reached a town, it could empty the streets within weeks. Doctors didn’t understand germs, so they tried everything from prayer to weird herb potions. Nothing worked.
Whole villages were abandoned. So many farm workers died that the survivors could finally demand higher wages, which slowly helped end the medieval system where peasants were tied to landowners. A horrible disease, in a strange way, reshaped Europe’s economy for centuries.
