What was the Black Death?

The Black Death was one of the deadliest catastrophes in human history: a pandemic that swept through Europe, the Middle East, and North Africa between roughly 1347 and 1351, killing an estimated third to half of Europe's population, tens of millions of people, in the span of just a few years. Whole villages were emptied, cities lost enormous shares of their inhabitants, and the scale of death was so vast it overwhelmed the ability of the living to bury the dead. The name Black Death came later; contemporaries often called it the Great Mortality or the Pestilence.

The cause was the bacterium Yersinia pestis, spread primarily by fleas that lived on black rats, which traveled along trade routes and aboard ships, carrying the disease from Central Asia into Europe with terrifying speed. It struck in horrifying forms, the bubonic version producing the swollen, blackened lymph nodes (buboes) that gave it part of its imagery, and a pneumonic form that spread person to person through the air and killed even faster. Medieval medicine had no understanding of germs and no effective treatment, so people blamed bad air, divine punishment, or scapegoated minorities, leading to horrific persecutions. The aftermath reshaped Europe: the massive loss of workers gave surviving peasants unprecedented bargaining power, helping erode serfdom and feudalism, raising wages, and shifting the social and economic order in ways that some historians see as clearing ground for the changes leading toward the Renaissance and the modern age. The disease never fully disappeared, recurring in waves for centuries.