The Black Death was a pandemic in Europe and Asia during the 14th century. This outbreak of disease was at its worst between 1347 and 1351. It killed between 75 million and 200 million people across Europe, the Middle East, India, and China.

Historians cannot be certain which disease caused the Black Death. However, most think the disease was the bubonic plague. This is a bacterial infection caused by the Yersinia pestis species of bacteria.

The Black Death may have begun in Central Asia or East Asia. It definitely appeared in Crimea in 1347. It was probably carried by fleas living on black rats. These rats traveled on Genoan ships and brought the plague to port cities around the Mediterranean. Rats may also have traveled along trade routes like the Silk Road, bringing infected fleas to European cities. When these fleas bit humans, they infected them with the plague by injecting a little bit of Y. pestis bacteria into the wound. Symptoms would start three to seven days later.

Not everybody agrees that plague caused the Black Death. Some historians have suggested that anthrax or a viral hemorrhagic fever caused the pandemic.

Impact 
The disease killed around a third of Europe's population. Some areas were less affected than others. At least 75-200 million people across Eurasia died in the Black Death pandemic.

Until the 1700s, the plague seems to have reappeared in Europe at least once every generation. Some of these smaller plagues were more intense than others, and caused more deaths.  Later outbreaks include the Italian Plague of 1629-1631, the Great Plague of London (1665–1666), the Great Plague of Vienna (1679), the Great Plague of Marseille in 1720–1722, and the 1771 plague in Moscow. The most virulent form of the plague seems to have disappeared from Europe in the 18th century.

The Black Death had a very big effect on Europe's population. It changed Europe's social structure. It was a serious blow to the Roman Catholic Church and resulted in widespread persecution of minorities such as Jews, Muslims, foreigners, beggars and lepers. The uncertainty of daily survival influenced people to live for the moment, as illustrated by Giovanni Boccaccio in The Decameron (1353).

At the time, fourteenth-century European writers called the pandemic the "Great Mortality." After later outbreaks, it got the name 'the Black Death'.

Media 
The Black Death appears in some modern literature and media, used as a subject or a setting. For example, Edgar Allan Poe's short story The Masque of the Red Death (1842) is set in an unnamed country during a fictional plague that shares many things in common with the Black Death.

Albert Camus's writings use this theme too. His novel The Plague (1947) is set against an outbreak of the plague in Algeria, and discusses how people handle the epidemic.

Medical aspects 
In humans, the bubonic plague causes fevers, severe flu symptoms, and buboes. Buboes are large swellings filled with pus. They usually appear in the groin, under the arms, on the thighs, and behind the ears. Buboes are a black and purple colour; this may be how 'The Black Death' got its name. The disease was painful, and many victims died horrible deaths.

The medical knowledge of the time was based on Hippocrates' theory of humorism. This theory said the body consists of different fluids. If they are in harmony, a person is healthy. If they are not, disease results. Very often, diseases were also seen as a punishment from God.

The theory of humorism does not explain why disease spreads from one person to another. Most people thought that infection was caused bymiasma ("bad air"). The bad air could come from within the earth, and thereby cause the disease. Remedies against the disease included opening only north-facing windows; not sleeping during the day; and not working too hard.

In 1348, Philip VI of France asked the Faculty of Medicine of the University of Paris about the cause of the Black Death. The Faculty concluded that the pandemic was caused by a bad conjunction of Jupiter, Saturn and Mars on 20 March, 1345. Since this answer was based on science (astrology), many people believed it, and it was translated into many languages.

Because nobody understood what caused the plague, doctors had no effective treatments. Often, doctors simply told their patients to go to Confession, so that their sins would be forgiven if they died. Eventually, the pandemic caused doctors to change their ideas about how the human body worked. Gradually they moved away from the theories of Hyppocrates and Galenos, and towards empirical science. Just 200 years later, Girolamo Fracastoro discovered that diseases spread through infection.

Germ warfare 
Mongol forces used the plague as a biological weapon in 1347. This was one of the earliest uses of germ warfare in history.

On the Crimean Peninsula, Mongol forces were fighting for control of Caffa, a Black Sea port (now Feodosiya, Ukraine). At that time, Caffa was a Genoese trade centre. Mongol forces began a siege. During the siege, they are reported to have catapulted plague-infested bodies over the walls into the city. Genoans fled the siege, using ships. Some historians believe the Caffa refugees brought the plague back to Italy with them, starting the Black Death pandemic.

Related pages 
 Great Plague of London

References

Other websites

Primary sources online 
 Agnolo di Tura's account 
 Gabriele de' Mussi's account 
 Marchionne di Coppo di Stefano Buonaiuti's account 
 A Petrarch account  and More quotes from Petrarch

Secondary sources online 
 The History Guide "Satan Triumphant: The Black Death"
 Symptoms, causes, pictures of bubonic plague
 Overview of the black death
 BBC news story on controversy over Black Death origins
 Examination of "Ring around the Rosy"'s relationship to the plague
 Black Death Overview from BBC history
 Plague and Public Health in Renaissance Europe. Primary source documents and analyisis
 Secrets of the Dead . Mystery of the Black Death  PBS
 Pandemics in Eastern Europe 

Plague pandemics
Middle Ages