The Black Death was the plague that killed an estimated one-third of Europe’s population in the 14th century. The pandemic reached Europe in 1347 and caused the most devastating mortality crisis in medieval European history.
The disease was primarily associated with the bacterium Yersinia pestis, which could spread through infected fleas carried by rodents. It appeared in several forms, including bubonic plague, which caused swollen lymph nodes called buboes, and pneumonic plague, which could spread through respiratory droplets.
The pandemic moved through Mediterranean ports and trade routes before spreading across Europe, North Africa, and parts of Asia. Estimates vary, but roughly 25 million Europeans may have died, with some regions suffering far higher losses than others. Labour shortages disrupted agriculture, trade, and traditional social relationships.
A common mix-up is calling every medieval epidemic “the Black Death.” The term usually refers specifically to the major pandemic of the mid-14th century, not all later plague outbreaks. Smallpox and typhus were different diseases, while the Spanish flu occurred in the 20th century.