The Black Death
The Black Death was a form of the plague. Just as Europe was finding its feet after the Dark Ages it suffered a catastrophic setback in the form of disease. Originating in Asia the bubonic plague took hold rapidly in Europe, spread by fleas carried on rats that flourished in the overcrowded medieval towns.
So called because it causes buboes or boils to erupt under the skin, bubonic plague reached Britain throught the port of Melcombe (present day Weymouth Harbour) in 1348, killing almost half of the population in a few months.
The epidemic had such a profound effect on the infrastructure of Europe that it became known as the Black Death.