The Black Death, or Black Plague, was one of the most devastating pandemics in human history. It began in South-western or Central Asia and spread to Europe by the late 1340s. The total number of deaths worldwide from the pandemic is estimated at 75 million people; there were an estimated 20 million deaths in Europe alone. The Black Death is estimated to have killed between a third and two-thirds of Europe's population.
The same disease is thought to have returned to Europe every generation with varying degrees of intensity and fatality until the 1700s. Notable later outbreaks include the Italian Plague of 1629-1631, the Great Plague of Seville (1647-1652), 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. There is some controversy over the identity of the disease, but in its virulent form it seems to have disappeared from Europe in the 18th century.
The Black Death had a drastic effect on Europe's population, irrevocably changing Europe's social structure. It was a serious blow to the Roman Catholic Church, Europe's predominant religious institution at the time, and resulted in widespread persecution of minorities such as Jews, Muslims, foreigners, beggars and lepers. The uncertainty of daily survival created a general mood of morbidity influencing people to "live for the moment", as illustrated by Giovanni Boccaccio in The Decameron (1353).
The initial fourteenth-century European event was called the 'Great Mortality' by contemporary writers and, with later outbreaks, became known as the 'Black Death'. It has been popularly thought that the name came from a striking late stage sign of the disease, in which the sufferers' skin would blacken due to subepidermal haemorrhages (purpura), and extremities darken with gangrene (acral necrosis). However, the term most likely refers to the figurative sense of 'black' (glum, lugubrious or dreadful).
Because the Black Death was, according to historical accounts, characterized by buboes (swellings in lymph nodes), like the late 19th century Asian Bubonic plague, scientists and historians assumed at the beginning of the twentieth century that the Black Death was an outbreak of the same disease, caused by the bacterium Yersinia pestis and spread by fleas with the help of animals like the black rat (Rattus rattus). However, this view has recently been questioned.
Nevertheless, compelling descriptions of the clinical disease in literature, including well-researched if second-hand accounts in historical fiction (see Daniel Defoe's A Journal of the Plague Year), offer compelling decription of the recognised disease - which in the context of such an epidemic, could be little else.