Fourteenth Century people referred to the Black Plague as the Great Plague. The term Black Death was first coined in the Nineteenth Century in reference to the appearance of those suffering from the disease. Supposedly the skin would darken, or blacken, due to hemorrhaging just under the skin, and the extremities might also blacken with gangrene.

There are several theories as to the cause of the disease. According to one theory the disease was caused by a bacteria, Yersinia pestis, which was spread by fleas carried by animals such as rats. Some modern researchers think this may only have been part of the story because there is evidence to suggest that the disease may even now be lying dormant in soil. Another idea put forth is that the historic pandemic of the Fourteenth Century may have been the result of more than one disease. There may have been infectious diseases caused not only by Yersinia pestis, but also by another bacteria, Bacillus anthracis, more commonly known as Anthrax.

In addition to exposure to bacteria, there is the probability that the high mortality of the Black Plague had other contributing factors.

During the Middle Ages there occurred a climatic phenomenon in Europe known as the Medieval Warm Period. During this period the climate in Europe tended to be so mild that it was possible to grow wine grapes in England! This environment was so conducive to farming that the population soared, witch in turn lead to overcrowding, especially in the cities.

At the beginning of the Fourteenth Century the climate began to change. Not only did the winters get colder, but the summers were colder and wetter, as well. This lead to crop failure on a large scale , and from 1315 to 1317, The Great Famine. Some areas are estimated to have lost as much as 30% of their population. Those that survived the cold, wet climate and the famine, could certainly be expected to be in a weakened condition.

The Fourteenth Century is thought to be the beginning of what has come to be known as The Little Ice Age. This cold period lasted, by most accounts, into the Nineteenth Century. Growing seasons were shorter, Winters were longer and widespread hunger persisted even after the Great Famine of 1315 to 1317.

Into this situation came the tendency for people to move and travel due to the crusades. Trade from Asia brought disease to a weakened population and in 1348 the Great Plague pandemic began.