Plague of Justinian, 541 to 750
The Plague of Justinian is one of the most extreme instances of death and disease in recorded human history. The death toll reached millions. The plague began in the outer parts of the Byzantine Empire, reaching the capital city of Constantinople a year later, in 542. Even the Emperor Justinian himself contracted the plague, but survived. Outbreaks continued for the next 200 years, and impacted not only the massive Byzantine Empire, but also the Sassanid Empire, and port cities around the Mediterranean.
The cause of the Plague of Justinian is now known; this was one of the first confirmed instances of Yersinia Pestis. This is the same bacteria that caused the Black Death 700 years later. Deaths may have totaled as many as 25 to 50 million over the course of the pandemic, or more than 13 percent of the global population at the time. The pandemic should be considered global, although of course people in the Americas and elsewhere were unharmed. Genetic studies have shown that the origins of Yersinia Pestis for the Plague of Justinian, as for the Black Death, were in China. The Plague of Justinian was the first recorded, historical instance of bubonic plague.
The city of Constantinople imported massive amounts of grain to feed its people. It’s likely that the plague arrived on ships stocked with grain from Egypt, and infested with rats. The Byzantine historian Procopius recorded the plague in Egypt in 541. According to Procopius, at its height, the plague killed 10,000 people per day in the city of Constantinople. While this number may not be accurate, the city was certainly dealing with massive numbers of deaths, issues with body disposal, and economic and legal disruptions.
The Plague of Justinian significantly weakened the Byzantine Empire. When the Plague of Justinian struck, Justinian’s armies were on the verge of reclaiming Italy and reuniting East and West in a single empire for the first time since the division of the Roman Empire.
It allowed other groups, including the Goths and Anglo-Saxons to gain power. The Romano-Britons relied heavily on trade with Gaul, so were impacted by the spread of plague, and likely lost large numbers to the plague. More isolated Anglo-Saxons were able to fill the void, gaining political power of their own.