Tatar Plague (Fidem Pacis)

The Tatar Plague was a major outbreak of the bubonic plague that was active in Europe and the Middle East from roughly 1347 to 1351, but is believed to have originated some years before that in central Asia. It is named for the Mongols, or Tatars as they were contemporaneously known in Europe, who played an important role in spreading the plague throughout Eurasia.

The plague killed an estimated 10 million people and crippled the economy for a decade. It's believed however that the death toll could potentially have been many times worse, perhaps comparable to the 6th century Plague of Justinian, had it not been for major developments in hygiene and public health in the last hundred years. Indeed, in some parts of eastern Europe where hygiene theory was not so advanced, the plague killed up to 40% of the population in places, and is even today known there as the Death Black Death. By comparison, Rome, Persia, Egypt, Italy and most of the West survived relatively unscathed.

The plague would recur in later generations, but each time medicine had become more advanced and more able to deal with it. By the end of the 16th century the plague, and other pandemics like it, had been almost eradicated in developed parts of the world.