What we now call the Black Death was actually the second of three major bubonic plague pandemics: the first known is the Justinian Plague, which centered around Byzantium in 541–542 AD, reoccuring sporatically until around 750 AD. It is estimated that anywhere from 25 to 100 million people died. The second plague occurred in Europe and Asia in the mid-fourteenth century, carrying off some thirty to sixty percent of the population. This "Great Mortality' or 'Great Pestilence,' as it was then called, is the most catastrophic pandemic ever recorded in human history. It would shake the social and economic foundations of Europe.