BIBLE HISTORY DAILY

Tracing the Justinian Plague

New evidence of the world’s first plague pandemic

The Justinian Plague (c. 541–750 CE) was one of the deadliest pandemics in human history. The Byzantine chronicler Procopius recorded that the plague claimed the lives of 10,000 people per day in the city of Constantinople alone. Despite the plague’s massive impact, its specific cause has remained elusive. Publishing in the journal Genes, a team of researchers identified evidence of Yersinia pestis—the same bacterium that caused the Black Death—from a sixth-century mass grave at the Roman site of Jerash in northern Jordan. The discovery, made near the epicenter of the pandemic, is some of the clearest evidence yet that plague was caused by the deadly bacterium.

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A Pandemic in the Empire

Often called the “first plague pandemic,” the Justinian Plague is estimated to have killed around a quarter of the population of Europe, the Middle East, and North Africa. First appearing in the city of Pelusium in northern Egypt, the plague quickly spread around the ancient world. However, the plague itself left little trace on the bodies of those it killed, leaving the exact cause of the illness up for debate. Previous studies in Western Europe identified evidence of Yersinia pestis on corpses from this time, but since such studies focused on sites beyond the borders of the Byzantine Empire, there remained uncertainty as to whether such deaths were connected the Justinian Plague.

As such, the researchers studied a site much closer to the plague’s epicenter, the major Roman-Byzantine trade city of Jerash (ancient Gerasa), located about 30 miles north of Amman in modern Jordan. The site’s impressive hippodrome, originally built for chariot racing, was used primarily as a dump site by the sixth century, and with the spread of the Justinian Plague, the hippodrome took on a much more gruesome role: a mass grave for plague victims. Excavations of two of the chambers in the hippodrome revealed the burials of roughly 150 adults and 80 children.

With the goal of identifying the specific cause of death, researchers utilized whole-genome sequencing on teeth from five individuals buried at the hippodrome. These teeth revealed that the plague victims carried nearly identical strains of Yersinia pestis, suggesting a very rapid spread of the outbreak, consistent with historical sources. This discovery provides some of the clearest evidence yet that Yersinia pestis caused the Justinian Plague to spread across the lands of the Byzantine Empire.

“The Jerash site offers a rare glimpse of how ancient societies responded to public health disaster,” said Rays Jiang, lead investigator in the study and professor at the University of South Florida, in a press release. “Jerash was one of the key cities of the Eastern Roman Empire, a documented trade hub with magnificent structures. That a venue once built for entertainment and civic pride became a mass cemetery in a time of emergency shows how urban centers were very likely overwhelmed.”

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Despite both the Black Death and the Justinian Plague being caused by Yersinia pestis, a separate study suggests the plagues developed from separate and unrelated strains of the bacterium. Researcher believe both plagues rose independently, likely having circulated for millennia among human and animal populations before erupting in multiple waves across different regions and eras. Although much less deadly, a third major Yersinia pestis pandemic took place in the 19th and 20th centuries, leading to the deaths of roughly 12 million people. Even today, occasional infections with the bacterium are known, with a resident of Arizona dying from the bacterium in July 2025.

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Related reading in Bible History Daily

Justinian Plague Linked to the Black Death

Israeli Archaeologists Discover Byzantine Quarry and Possible Site of Sixth Century Miracle

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