Black Death

The speed with which the sickness swept inland from the ports puzzled contemporaries and continues to occupy modern researchers. While the disease was carried across the seas by fleas living on black rats aboard Genoese vessels, its rapid, devastating march across the European continent suggest that it did not rely on rodent vectors alone. Once ashore, the Black Death likely spread directly from person to person as pneumonic plague, an airborne variation that bypassed the slow cycle of rat-to-flea-to-human transmission. In Europe, where the memory of the Great Famine of 1315–1317 was still fresh in the minds of the elderly, this new horror was unmatched. Between 1346 and 1352, the pandemic tore through the continent, killing as many as 50 million people—perhaps half of Europe’s fourteenth-century population. Latin chroniclers of the era struggled for language to describe the scale of the loss, recording the catastrophe under the names pestis, epidemia, or simply magna mortalitas—the Great Death.

Further east, the pandemic shook the foundations of empires that had once seemed invincible. In China, the Yuan Dynasty struggled under a cascade of disasters: the plague was accompanied by widespread flooding and famine, a combination that shattered the administrative capability of the Mongol rulers and undermined their legitimacy. This triple crisis fueled the Red Turban Rebellion, which began around 1351 and ultimately led to the overthrow of the Mongols and the establishment of the Ming Dynasty in 1368. In the Golden Horde, the loss of the ruling elite and the sudden depopulation of the lucrative trade routes along the Volga triggered a prolonged domestic collapse. By 1359, the Horde descended into a chaotic period of civil war known as the "Great Troubles," weakening its grip on its Russian vassals and paving the way for the rise of the Grand Duchy of Moscow. Even India, under the Tughlaq Dynasty of Muhammad bin Tughlaq, recorded massive, sudden outbreaks of pestilence in 1334 and 1344. Though the traveler Ibn Battuta described an army decimated almost instantly by high fevers near Bidar and Warangal, the lack of distinct physical markers like buboes in his accounts leaves it unclear whether India suffered from Yersinia pestis or another tropical killer like cholera or malaria.

The term "Black Death" itself was not used by the people who lived through the fourteenth-century cataclysm. While the ancient Greek poet Homer had once described the monster Scylla as having mouths "full of black Death," and the medieval Belgian astronomer Simon de Covino had used mors nigra in a 1350 poem to describe the fatal end of the sickness, the name was not a contemporary label for the pandemic. Instead, it was popularized centuries later by Danish and Swedish chroniclers who spoke of den sorte død. The English language did not adopt the term until the 1750s, when writers translated the Scandinavian texts, forever fixing the dark moniker to the event.

The pandemic did not simply vanish after its initial fury subsided in 1352. It marked the beginning of the second plague pandemic, a centuries-long era of biological insecurity. Outbreaks recurred periodically across Europe, the Middle East, and the rest of the world, preventing populations from recovering. Due to the recurring visitations of the plague and the broader crises of the Late Middle Ages, Europe’s population did not return to its early fourteenth-century levels until the sixteenth century, while the global cycle of outbreaks persisted into the early nineteenth century. By the time the bacterium finally receded, it had permanently redrawn the political, social, and economic maps of Eurasia, bringing down dynasties, fracturing empires, and leaving behind a transformed world that had learned, at a terrible cost, just how small and interconnected it had become.