Estimates of the Plague of Justinian's death toll in Constantinople 541

The Plague of Justinian was the first major bubonic plague pandemic recorded in Europe, and was the first pandemic to ever be described or documented with any relative reliability. The plague takes its name from Emperor Justinian I, who ruled the Byzantine Empire (Eastern Roman Empire) at the time of the outbreak. The Byzantine capital of Constantinople (also known then as Byzantium, and Istanbul today) was the hardest hit city during the pandemic, and where the majority of sources are from. Until recently, it was only assumed that the outbreak was bubonic plague, due to the symptoms described by contemporary historians, but scientists were able to confirm that it was in fact Yersinia pestis (the bacterium that causes plague) in 2013.

Constantinople overwhelmed

It is thought that the plague was brought to Constantinople by Egyptian grain merchants, although a recent theory suggests it was brought from the Eurasian Steppes (from where Yersinia pestis originates) to Europe by Hunnic tribes. While the exact origins of the plague remain unclear, it is estimated that up to 300,000 people died in Constantinople in the first year of the outbreak. Contemporary sources claim that there were approximately 5,000 deaths in the city every day at the height of the pandemic, even reaching highs of 10,000 on some days.

Constantinople outbreak was unique

A 2019 study, conducted by researchers from Jerusalem and Princeton raises some important questions about the scale of the outbreak across Europe. They dispute the claim by some modern historians that this pandemic killed up to half of the population of the Mediterranean (or that it was instrumental to the collapse of the Eastern Roman Empire), instead suggesting that the scale of the outbreak in Constantinople was unique to that city. They use a variety of literary, archeological, and scientific sources to show that the plague was unlikely to have reached this magnitude across other cities at the time, nor did it spread in the same way that the Black Death did six centuries later. While future studies are likely to provide further insight into these theories, it is important to remember this contrasting hypothesis when studying pre-2019 sources.