The Black Death was one of the deadliest pandemics in human history, started in 1347 and peaking in Europe between 1348 and 1350. It is widely thought to have been an outbreak of bubonic plague caused by the bacterium Yersinia pestis, but this view has recently been challenged. Usually thought to have started in Central Asia, it had reached the Crimea by 1346. From there, probably carried by fleas residing on the black rats that were regular passengers on merchant ships, it spread throughout the Mediterranean and Europe.
The Black Death is estimated to have killed 30% to 60% of Europe’s population, reducing the world’s population from an estimated 450 million to between 350 and 375 million in 1400. This has been seen as creating a series of religious, social and economic upheavals which had profound effects on the course of European history. It took 150 years for Europe’s population to recover. The plague returned at various times, resulting in a larger number of deaths, until it left Europe in the 19th century.
Signs and symptoms
The three forms of plague brought an array of signs and symptoms to those infected. The septicemic plague is a form of “blood poisoning,” and pneumonic plague is an airborne plague that attacks the lungs before the rest of the body. The classic sign of bubonic plague was the appearance of buboes in the groin, the neck and armpits, which oozed pus and bled. Most victims died within four to seven days after infection.
Figures for the death toll vary widely by area and from source to source as new research and discoveries come to light. It killed an estimated 75–200 million people in the 14th century. According to medieval historian Philip Daileader in 2007:
The trend of recent research is pointing to a figure more like 45% to 50% of the European population dying during a four-year period. There is a fair amount of geographic variation. In Mediterranean Europe, areas such as Italy, the south of France and Spain, where plague ran for about four years consecutively, it was probably closer to 75% to 80% of the population. In Germany and England … it was probably closer to 20%