FactSentinel

The claim that the Black Death killed roughly a third or more of Europe's population in the 14th century is supported by the consensus among historians and demographers. The pandemic reached Europe in 1347 through Mediterranean trade ports and spread across the continent by about 1351. Most modern estimates put the death toll between 30 and 50 percent of the European population, which amounts to roughly 25 to 50 million people. Some regions, including parts of Italy, England, and Mediterranean France, may have lost even more, while others, such as parts of Poland, Bohemia, and some areas of the Low Countries, appear to have been affected less severely.

The evidence comes from several independent sources. Church records of clergy deaths and replacements, manorial court rolls, tax and census documents, wills, and burial records all show sharp spikes in mortality. English records, for example, suggest that a large share of beneficed clergy died in 1348 and 1349. Archaeological work, including mass graves in London and elsewhere, supports the written accounts. Genetic studies of ancient DNA recovered from victims have confirmed that the bacterium Yersinia pestis was the cause.

A common misconception is that the figures are precise. Medieval record-keeping was incomplete, so estimates carry real uncertainty, and a minority of scholars have argued for somewhat lower regional figures. Another misconception is that the plague struck once and vanished. Outbreaks recurred for centuries, which kept populations depressed well into the 15th century.