Plague of Justinian (541): The First Recorded Plague Pandemic

The Plague of Justinian was the first known pandemic of bubonic plague, an outbreak caused by the bacterium Yersinia pestis that appeared in Egypt in 541 and struck Constantinople in 542, during the reign of the Eastern Roman emperor Justinian I. It spread across the Mediterranean, into Persia and as far as Britain, and returned in waves for about two centuries until around 750. Eyewitnesses described mass death on a terrifying scale, and ancient DNA has now confirmed the cause, though historians still argue over how many people died.

Background: an empire on the move

In 541 the Eastern Roman Empire was at the height of its ambitions. Justinian’s armies had conquered Vandal North Africa and were fighting in Italy and against Persia. Grain ships, merchants, pilgrims and soldiers moved constantly around the Mediterranean, linking Egypt, Constantinople and the western provinces.

The plague bacterium normally lives among wild rodents and is spread by their fleas. When it reaches rats living close to people, such as the black rat common in late Roman ports and granaries, infected fleas can pass it to humans. The busy trade routes of the empire offered ideal conditions for its spread.

Some historians also point to environmental stress. A series of volcanic eruptions in 536 and around 540 cooled the Northern Hemisphere and caused poor harvests, a period scientists call the Late Antique Little Ice Age. Whether this helped trigger the pandemic is debated. Cold, hungry populations may have been more vulnerable, and changing conditions may have affected rodent numbers, but the link remains a hypothesis rather than an established fact.

Outbreak and spread

According to Procopius, the disease first appeared in 541 at Pelusium, on the eastern edge of the Nile Delta near modern Port Said. From there it spread west to Alexandria and the rest of Egypt, and east into Palestine and Syria.

It reached Constantinople in the spring of 542 and raged for about four months. Procopius, who lived in the city, says deaths rose to 5,000 a day and then to 10,000 and more. The Syriac churchman John of Ephesus, who travelled through Palestine and Asia Minor during the outbreak, describes deserted villages and fields, and claims that officials counting the dead in the capital gave up after passing 230,000. These figures are impressions rather than records, but they convey the shock of the moment.

The plague moved along shipping lanes and roads into Persia, where it struck the army of Khosrow I, and westwards to North Africa, Italy, Spain and Gaul. Gregory of Tours describes later outbreaks in Gaul, including at Clermont. By the 540s and later decades it had reached the British Isles, where DNA from a burial at Edix Hill in Cambridgeshire has confirmed infection.

Symptoms and experience

Procopius gives a careful description. Victims had a sudden fever, often mild at first, followed within days by swellings, known as buboes, in the groin, armpits or behind the ears. Some fell into a deep coma or delirium; others developed black pustules or vomited blood. Many died within a few days, but some survived after the swellings burst.

Doctors were helpless, and Procopius notes that they could not predict who would live. The disease did not appear to spread simply by touch, since those who nursed the sick did not always catch it, a detail that fits transmission by fleas.

Modern medicine distinguishes several forms of plague. Bubonic plague, with its swollen lymph nodes, matches most of the ancient descriptions. Pneumonic plague, which infects the lungs, can pass directly from person to person through coughing and is almost always fatal without treatment; the reports of victims vomiting blood suggest that it also occurred. Today plague can be treated with antibiotics, but in the sixth century no effective remedy existed.

Social life broke down in Constantinople. Shops closed, trades stopped and food ran short. Justinian appointed an official named Theodore to oversee burials with public funds. When graves ran out, according to Procopius, bodies were piled into the towers of the city walls at Sycae, across the Golden Horn, and onto boats that were set adrift.

The emperor and the state

Justinian himself caught the plague in 542 and recovered. His illness caused alarm at court, and rumours that he had died led some officers to discuss the succession, which later brought Belisarius under suspicion.

The pandemic hit the empire’s finances and manpower. Fewer taxpayers meant less revenue, yet Justinian continued his wars in Italy and against Persia. Procopius complains that surviving landowners were made to pay the taxes of dead neighbours. In 544 Justinian issued a law, Novel 122, declaring that the disease had passed and ordering wages and prices to return to their earlier levels, a sign that labour had become scarce.

Some historians see the plague as a turning point that undermined Justinian’s reconquest and weakened the empire before the Arab conquests of the seventh century. Others think its long-term effects were more limited.

Recurrences over two centuries

The first outbreak of 541–549 was not the end. Plague returned roughly every ten to twenty years, with perhaps 15 to 18 major waves recorded across the Mediterranean and the Near East until about 750.

The disease also shaped the history of the Near East. A plague known as the Plague of Sheroe struck the Sasanian Persian capital Ctesiphon in 627–628, and the Plague of Amwas in 638–639 killed many soldiers of the new Arab Muslim armies in Syria, including their commander Abu Ubayda. Later outbreaks under the Umayyad caliphs were recorded in Iraq, Syria and Egypt.

Evagrius Scholasticus, a lawyer in Antioch, caught the disease as a schoolboy in the 540s and survived. Writing around 593, he recorded that later outbreaks had killed his wife, several of his children and grandchildren and many other relatives. In Rome, Pope Pelagius II died of plague in February 590, and his successor Gregory the Great led penitential processions through the city as the epidemic continued.

The last great outbreaks in the eastern Mediterranean occurred in the 740s, including a severe epidemic in Constantinople in 747. After about 750 the disease disappeared from Europe and the Near East until the Black Death of 1347 (see Black Death).

How many died?

The death toll is one of the most debated questions in early medieval history. Older works often quote 25–50 million deaths across the whole pandemic, or claim that up to half of the population of the Mediterranean died. Such figures rest on few reliable numbers.

Some historians, such as Kyle Harper, argue that the plague was catastrophic, perhaps killing a large fraction of the population of Constantinople and other affected regions in the first wave. In 2019 a team led by Lee Mordechai and Merle Eisenberg argued in a widely discussed study that papyri, coins, inscriptions and pollen data show little sign of a sudden collapse, and that the pandemic’s impact has been exaggerated.

Most scholars now agree that mortality varied greatly from place to place and that the true scale cannot be measured precisely. Contemporary eyewitnesses in Constantinople, Antioch and Palestine nonetheless left no doubt that local death rates in 542 were extremely high.

Ancient DNA evidence

For a long time some historians doubted that the sixth-century pestilence was really plague. Ancient DNA has settled the question. In 2013 and 2014 researchers recovered Yersinia pestis genetic material and then a full genome from sixth-century graves at Aschheim, near Munich in Bavaria. Further genomes followed from Altenerding in Bavaria in 2016 and, in 2019, from sites in Germany, France, Spain and England.

The studies show that the pandemic strain belonged to its own branch of Yersinia pestis, which emerged separately from the strains behind the Black Death and later died out. Its closest relatives point to an origin among rodent populations in Central Asia, with the bacterium probably reaching the Mediterranean through trade routes.

By the numbers

Timeline

• 541: Plague appears at Pelusium in Egypt and spreads to Alexandria.
• Spring 542: Plague reaches Constantinople; Justinian falls ill and recovers.
• 543: The epidemic spreads through Italy and into the West.
• 544: Justinian’s Novel 122 tries to fix wages and prices at pre-plague levels.
• 558: A second wave strikes Constantinople.
• February 590: Pope Pelagius II dies of plague in Rome; Gregory the Great is elected.
• 664: A major outbreak strikes Britain and Ireland, recorded by Bede.
• 747: A severe outbreak in Constantinople, among the last of the pandemic.

Why it matters

The Plague of Justinian was the first of three great plague pandemics, followed by the Black Death and the Third Plague Pandemic. It shows how disease, trade and climate shaped the late Roman world and the reign of Justinian I, and modern DNA research has turned it into a key case study of how pandemics emerge and disappear.