The Black Death got its name from a combination of two things: the terrifying skin discoloration the disease caused in its victims, and a long literary tradition of using “black” to describe death itself. The name wasn’t actually used during the pandemic. People living through the catastrophe of 1347 to 1353 called it the “Great Pestilence” or the “Great Mortality.” The term “Black Death” came later, drawn from older Latin phrases and applied retroactively to the deadliest outbreak in recorded history.
What People Called It at the Time
During the 14th century, no one used the phrase “Black Death.” Survivors and chroniclers referred to the epidemic as the Great Pestilence or the Great Mortality, names that reflected what they saw around them: mass death on an almost incomprehensible scale. Recent research from Oxford suggests the first wave alone killed roughly 50% of the population in Western Europe, far higher than the older estimate of 25 to 33%. In England specifically, the population dropped from about 4.8 million in 1348 to 2.6 million by 1351, a loss of 46% in just three years.
The phrase “Black Death” as a label for this specific pandemic didn’t appear in print until 1631, when a Danish historian named J. I. Pontanus wrote in Latin: “Commonly and from its effects, they called it the black death.” Even then, Pontanus was writing nearly 300 years after the fact. The name gained wider use in the centuries that followed, eventually becoming the standard term in English by the 1800s.
The Latin Roots of “Black Death”
The Latin phrase behind the name is “atra mors,” and its meaning is more layered than a simple translation suggests. “Atra” can mean both “black” and “terrible” or “dreadful.” When the Roman philosopher Seneca used “mors atra” centuries before the medieval plague, he was describing the grim prognosis of disease, not the color of anyone’s skin. Homer used a similar image even earlier in the Odyssey, describing the monster Scylla’s mouths as “full of black Death,” a poetic way of saying death was dark, final, and horrifying.
By the 12th and 13th centuries, the French physician Gilles de Corbeil was already using “atra mors” to describe pestilential fever. So when later historians reached for a dramatic name for the 14th-century pandemic, the phrase was ready-made. It carried a double meaning: both the literal blackening of the body and the metaphorical darkness of the disaster.
The Disease That Turned Skin Black
The physical explanation for the name is just as important as the literary one. The plague, caused by a bacterium spread through flea bites (and sometimes through the air), produced visible and horrifying changes in the body. The most recognizable symptom was the development of buboes, swollen and painful lymph nodes that appeared in the groin, armpits, or neck near where the bacteria entered the body. These lumps could swell to the size of an egg or an apple.
But the truly “black” symptoms came from what the disease did to the blood. Victims developed severe bleeding problems, including sudden hemorrhaging beneath the skin. This created dark purple or black bruise-like patches across the body. In the most severe form of the illness, known as septicemic plague, the bacteria overwhelmed the bloodstream and caused tissue to die, particularly in the fingers, toes, and nose. These extremities could turn visibly black from gangrene. Skin sores formed black scabs. Bleeding from the mouth, nose, and other openings was common in advanced cases.
For people witnessing this in the 14th century, with no understanding of bacteria or infection, the blackening of a living person’s body must have seemed like something supernatural. It’s easy to see why the association between “black” and this particular plague stuck, even if the name took centuries to become official.
How We Confirmed the Cause
For a long time, historians debated whether the Black Death was really bubonic plague or some other disease entirely. That question was settled definitively through DNA analysis of human skeletons excavated from mass graves across Europe. Researchers extracted genetic material from bones buried in the Netherlands, France, and England, all from sites linked to the 14th-century pandemic, and identified unmistakable signatures of the plague bacterium.
Interestingly, the strains that caused the Black Death don’t match any of the modern varieties of the same bacterium still circulating today. Genetic analysis placed the medieval strains near a deep branching point in the bacterium’s evolutionary tree, meaning the Black Death was caused by an ancestral lineage that later gave rise to several distinct modern strains. The plague bacterium has continued to evolve in the nearly 700 years since, but its medieval ancestor was, by all evidence, extraordinarily lethal.
Why the Name Endured
Plenty of pandemics have killed enormous numbers of people, but few have names as vivid or lasting as the Black Death. Part of that staying power comes from the name’s precision: it captures both the scale of the catastrophe and the specific, visible horror of the disease in a single phrase. “Great Pestilence” is descriptive but generic. “Black Death” is unforgettable.
The name also benefited from timing. It gained popularity during the 18th and 19th centuries, when European historians were actively constructing narratives about the medieval period. Writers needed a term dramatic enough to convey an event that reshaped the continent’s population, economy, and social structure. A pandemic that may have killed half of Western Europe deserved a name that sounded like it.