In the middle of the 7th century, a plague swept through the walled city of Jerash, in what is now modern-day Jordan.
Ceramicists abandoned their workshops under the Hippodrome, leaving unfired pottery in their haste. Young and old alike succumbed to a bacteria called Yersinia Pestis, the same microbe responsible for the Black Death seven centuries later.
The city, unable to manage the dead and dying, converted those workshops into a mass grave.
"It was filled within days — hundreds of bodies," says Rays Jiang, a University of South Florida geneticist and lead author of a new study in the Journal of Archeological Science, highlighting the plague victims of Jerash. "There's no ceremony, there's no grave goods. It's a bare minimum to get the bodies disposed of and away from the city."
To understand the lives of the people who died at Jerash, Jiang gathered a team of eight experts from various specialties: archeology, molecular genetics, anthropology and chemistry. Their work helps illustrate the devastation of what is believed to be the first historically recorded pandemic, which began with the Plague of Justinian and killed tens of millions of people across the Mediterranean Basin, West Asia and Northern Europe from roughly 541 to 750.
According to Jiang's earlier work, plague microbes isolated from the bodies at Jerash were extremely similar — suggesting that the bacteria was highly contagious, spread rapidly and claimed its victims quickly, before it had a chance to mutate significantly.
"I did not know that so far back, a single strain of plague can spread so fast and kill so many," Jiang said. "All of the victims we found were killed by a single strain."
The city of Jerash was situated on a major trade route within the Eastern Roman Empire. It was known for manufacturing delicate ceramic serving dishes, sometimes painted with figures that had wide, expressive eyes. After the rise of Christianity, the passages under the Hippodrome, a stadium once used for chariot races and gladiator fights, were repurposed as workshops for dyeing fabric and making pottery.
Karen Hendrix, a University of Sydney archeologist who co-authored the study, says Jerash would have faced multiple waves of the plague before it came back with a vengeance around the year 650.
"The population of Jerash had fallen to about 10,000 people," Hendrix said. "Much of the previous architecture fell into disuse."
Without treatment, Y. Pestis kills about 60 to 100% of the people it infects. (Modern antibiotics, however, are extremely effective if the illness is diagnosed quickly.)
Turning these workshops into a mass grave must have been a desperate choice, the researchers say.
Jiang and her team extracted samples from several human teeth uncovered during excavations at Jerash in the 1980s and analyzed them using two technologies. First, they sequenced the plague victims' mitochondrial DNA and then conducted a stable isotope analysis. Certain isotopic markers, like carbon, nitrogen and oxygen, are found in tooth dentine, the layer found underneath tooth enamel. Dentine forms in early childhood and stays relatively stable, allowing experts to reconstruct a person's childhood diet from a preserved tooth.
The approximately 230 victims interred in the grave were men, women and children — some in the prime of their lives, says Jiang. The DNA also shows that they had ancestral ties to faraway places, including central Africa, eastern Europe and Anatolia. This data is affirmed by an isotope analysis, which showed that the plague victims grew up in different places.
"They had very different childhoods," Jiang said. "They ate different food. Some drank water from wells, some from cisterns, some from mountain streams."
This surprised the team members. While ancient populations in West Asia were very mobile and genetically diverse, Jiang says the people interred in the mass grave did not appear to be locals. They could have been visiting merchants, foreign workers, even enslaved people.
"Normal cemeteries could not handle more people, and this fraction was selected out," Jiang said. "It's most likely that they represent a section of society that was highly mobile and had come to the city."
It's rare to find cemeteries in the region that include burials of people with foreign ancestry. The mass grave at Jerash captures the diversity of the city at a moment in time — a pattern that was likely common throughout the ancient world but remains largely understudied.
"This combination exposes a demographic layer rarely captured in cemeteries: the steady trickle of economic migrants, itinerant laborers, climate-stressed families, pilgrims, soldiers, traders and displaced persons," the authors wrote in the study.
Ancient pandemics expert Nükhet Varlık with Rutgers University, who was not involved in this study, says the research aligns with known ways that ancient communities reacted to early pandemics. "It shows you a moment of crisis," she said. After earlier waves of plague killed large numbers of people, the city would need new sources of labor. Workers from elsewhere would arrive to fill the gap, and the cycle would repeat.
"Immigrants would come to the city looking for employment. And then the pandemic hits," Varlık said. "They're among the most vulnerable population."
To Varlık, the study is a reminder that the plague victims at Jerash were real people who lived full lives.
"But coming to the same city to die of the same disease," Varlık said. "It shows us the diversity of how people experience pandemics — which is a universal experience for humanity."
Shortly after the victims were buried under the Hippodrome, a major earthquake struck in the year 659. The structure collapsed, sealing the bodies inside. For the survivors in Jerash, the site would serve as a reminder of the danger of unchecked microbes, lurking in the ecosystem.
"Plague is so ancient and diverse. It's been with us for thousands of years — it's still here and it'll never go away," Jiang said. "But what can be managed, is how we manage its spread, containment and our response to it."
Durrie Bouscaren is an award-winning journalist covering migration, politics, and climate change —and sometimes archaeology—in the Middle East and Turkey.
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