The Plague The common carrier of the plague, the flea. A common prayer of the people during outbreaks of the plague. Since the reign of Justinian in 542 AD, man has one unwelcome organism along for the ride, Yersinia pestis. This is the bacterium more commonly known as the Black Death, the plague.
Plague is a disease of antiquity that has persisted to modern times.
Epidemic bubonic plague was vividly described in biblical and medieval times. The most known incidence of bubonic plague was in fourteenth century Europe. The Black Death which initiated the second wave of plague infection is historically the best known plague and the one that has been the most thoroughly studied. The role of trade and war in spreading the plague is very important. The plague, carried by shipborne rats and fleas, arrived in Europe at a time when natural and human problems had reached a crisis.