The Death Toll During the Plague of Justinian

Death Toll Plague of Justinian

The Plague of Justinian was a terrible event in the mid-6th century CE, the death toll of which is among the highest in world history.

In actuality the Plague of Justinian was a particularly severe outbreak of the bubonic plague. The outbreak in the 6th century lasted for nearly 200 years before ending, and is thus known as the First Plague Pandemic.

Later, a second (commonly referred to as the “Black Plague”) and third (China from 1855-1960) plague pandemic appeared. All three of these devastating pandemics were variations of bubonic plague that were thought to have been carried by rats—or fleas that used rats for transmission.

The timing of the Plague of Justinian was detrimental for the Emperor Justinian’s plans for the Byzantine Empire. Though Justinian envisioned a return to the Roman Empire’s former glory and territories, the dramatic population loss from the plague made the situation impossible.

It is likely that Justianian has been unfairly blamed for the pandemic, though some of his pandemic policies surely contributed to greater suffering. The city of Constantinople greatly suffered given its status as the capital and chief city of commerce in the Byzantine Empire.

Historians disagree on the death toll from the plague and its overall impact on the Byzantine Empire and Western Europe. Some state that while the first wave of the plague was particularly nasty, the other waves were more tame and the plague itself did not have a large impact in European affairs.

Others believe that the Plague of Justinian was the beginning of the end of the Byzantine Empire. These historians believe that following the first instance of bubonic plague, the empire was never the same and would decline slowly until the 15th century.

Justinian’s Conquests

The Emperor Justinian ruled the Byzantine Empire from 527 CE to 565 CE. The Byzantine Empire was equivalent to the Eastern Roman Empire. While the Western Roman Empire dissolved by 476 CE, the eastern portion, or Byzantine Empire as it was now called, remained.

Emperor Justinian had ambitions to return to the glory of the old Roman Empire. He hoped that the Byzantines could reconquer lost territories from the Western Roman Empire, including the illustrious city of Rome, and add to the prestige of the Byzantine Empire.

Justinian and the Byzantines gradually reconquered former Roman territories from the “barbarians” that overran and currently occupied them. The legendary general Belisarius led a majority of these military campaigns.

First the Byzantines took back the city of Carthage and the former North African province. The Kingdom of the Vandals that ruled there were taken by surprise and defeated soundly in a campaign lasting from 533-534.

Next Belisarius sailed north to the Italian peninsula. In an engagement known as the “Gothic War,” the Byzantines fought with the Ostrogothic Kingdom. In the first phase lasting from 535-540, Belisarius reconquered the entire Italian peninsula and expelled the Ostrogoths from their capital of Ravenna in the north.

Byzantine Empire map Justinian
The Byzantine Empire at its extent after reconquering North Africa, Italy and a portion of Spain via Wikimedia

The second phase of the conquest lasted from 541-554 and was a long, costly, and drawn out affair for the Byzantines simply attempting to maintain their newly-gained territories.

Later, in the early 550s, Justinian would reconquer the southern portion of the Iberian peninsula centered around Cartagena. The Visigothic Kingdom remained strong in the region which limited their ability to expand further from there.

These conquests helped to reunite the old Roman empire together for a brief period. Trade once again flourished across the Mediterranean Sea as commercial enterprises interconnected the many cities and ports within the empire.

Unfortunately the ease of transport within the Mediterranean region also allowed other, more detrimental forces to spread easily as well such as the infamous Plague of Justinian.

What Was the Plague of Justinian?

The Plague of Justinian was a devastating pandemic that ravaged the Mediterranean region from 541-549 CE. The initial outbreak of the plague may have only lasted for less than a decade, but historians estimate that the plague would return in waves over the next two centuries.

Anywhere from 14-21 waves would ravage the entire Mediterranean region, as well as central and northern Europe. At one point the plague reached as far north as the British Isles.

The name “The Plague of Justinian” is a bit of a misnomer. This would equate that all the plague outbreaks were the responsibility/fault of the first outbreak during Justinian’s reign. Instead, the term “Justinianic Plague” would be more accurate to suggest the long-lasting plague began during his rule.1

For centuries no one knew what caused the outbreak. Eventually, through the exhumed bodies of plague victims, modern technology was able to pinpoint the source of the disease.

Emperor Justinian mosaic plague
Mosaic of the Emperor Justinian (center ) via MET

As it turns out, the Plague of Justinian was a form of the deadly bubonic plague Yersinia pestis (Y. pestis). This meant that this variation of the bubonic plague was cousin to the plague responsible for the “Black Death” occurring centuries later.

For such an awful event in world history, there are very few primary sources on the plague. The best sources we have today are Procopius of Caesarea (Byzantine scholar) and John of Ephesus (Syriac church historian).

Both sources wrote how the plague devastated Byzantine populations. The city of Constantinople was hit particularly hard.

Scholars believe the plague likely began in either Egypt or Central Asia and spread rapidly via fleas that hosted the bacteria. The fleas hitched a ride on rats and/or humans and transportation between the interconnected Mediterranean cities helped spread the plague far and wide.

What was the Death Toll of the Plague of Justinian?

The bubonic plague was a terrible disease that rapidly infected the Mediterranean population and ground Byzantine operations to a halt. Recent estimates suggest that close to 25% of the population of the Mediterranean world perished. No one was spared as the plague affected members from all classes of society.

Peasant farmers, military members, and aristocratic nobles all caught and succumbed to the disease. Even the Emperor Justinian himself is said to have gotten the plague, though he survived the onslaught.

Symptoms of the disease included fever, chills, and swollen lymph nodes. Malaise, delirium, and a coma were also common symptoms and effects of the plague.

Typical plague victims have a high mortality rate estimated at between 68-78%. Despite this, death is not typically rapid. The Justinianic Plague was an exception in this case as historical accounts note that victims succumbed quickly to their ailments.2

In some cases death would come in as little as two days after symptoms showed. Those that put up a good fight would scarcely last five days.

The Plague of Justinian death toll chart

Procopius notes that people died faster than gravediggers could bury them, and the entire city of Constantinople smelled like death.

Estimates for the death toll of the Plague of Justinian are varied. One source notes that over 10,000 people perished in Constantinople in one day from the plague.

The Plague of Justinian death toll estimates in the city of Constantinople itself are as high as 55-60%. In a city with a population of ~400,000 at the time, this equates to nearly 240,000 deaths in just one city.

While traditional estimates state that the Plague of Justininian death toll was around 25-50% of the population of the Mediterranean world, recent analysis points towards the lower end of that spectrum.3

Without accurate historical records it is nearly impossible to come to an accurate number. The plague almost certainly hit cities harder than more rural populations given the ease of transmission from human to human.

Aftereffects of the Plague of Justinian

The Plague of Justininian carried massive repercussions for the Byzantine Empire and the larger Mediterranean world. The most extreme and dramatic interpretations state that the First Plague Pandemic brought about the decline of the Byzantine Empire and the end of antiquity.

The claims of the end of the Byzantine Empire are surely exaggerated given that the empire remained viable for another several hundred years after the first instance of the plague. However, there is a direct correlation between the onset of the plague and major issues occurring within the empire.

In the years prior to the onset of the plague Justinian had wracked up enormous amounts of debt in his campaigns of reconquest and vast construction projects. Though these recaptured territories would eventually pay for themselves, the initial campaigns put strains on the Byzantine economy.

Justinian Plague unfinished pillars Phillipi
Pillars of an unfinished basilica likely caused by the Justinian Plague via Wikimedia

The emperor raised taxes on citizens to help pay for these military conquests. With so many dead from the pandemic, the tax burden was even greater on those that remained.

With the plague affecting populations all over, famine was common, likely due to a lack of available workers to collect the harvests.

Justinian’s newly-reunited empire suffered greatly and became prone to invasions from neighboring kingdoms such as the Lombards in Italy. The military proved highly susceptible to the disease due to the close quarters of troops and oftentimes a lack of sanitary conditions.

Just decades after the successful campaigns, the Byzantine Empire would lose much of its territorial gains. Though claims of a rapid Byzantine decline following the plague are exaggerated, it is true that the Byzantine Empire reached its territorial extent under Justinian.


1) Benedictow, Ole. J. “The Justinianic Plague Pandemic: Progress and Problems.” Early Science and Medicine, vol. 14, no. 4, 2009, pp. 543–48. JSTOR,

2) Allen, P. “THE ‘JUSTINIANIC’ PLAGUE.” Byzantion, vol. 49, 1979, pp. 5–20. JSTOR,

3) Mordechai, Lee, et al. “The Justinianic Plague: An Inconsequential Pandemic?.” PNAS, vol 116, no. 51, 2019,

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