A sixth century mass grave located in the Jordanian city of Jerash has been identified as the oldest genetically confirmed plague-related burial and the first of its kind in the Eastern Mediterranean, according to a study published in February in the Journal of Archaeological Science.

DNA extracted from the remains of more than 230 of those buried beneath Jerash's second century hippodrome tested positive for Yersinia pestis, the bacterium that caused the bubonic plague and the First Pandemic, also known as the Plague of Justinian, which spread across the Byzantine Empire between 541 and 750 CE.

Further analysis also confirmed that all Y. pestis genomes recovered from the site belonged to a single, uniform strain, the study noted, indicating that the victims died during a single outbreak rather than across several different ones.

Archaeological evidence has dated the burials to between 640 and 659 CE, and found that the grave had been sealed by an earthquake that collapsed the hippodrome's stone seating not long after.

According to the study, the grave predates the Black Death burial pits from medieval Europe by approximately 800 years.

"The earlier stories identified the plague organism,” explained lead researcher Rays H. Y. Jiang, an associate professor at the USF's College of Public Health. “The Jerash site turns that genetic signal into a human story about who died and how a city experienced crisis.''

According to the study, the bodies were buried within the hippodrome rapidly and with minimal funerary structure, consistent with accounts of mass-casualty events that overwhelm a city's normal burial capacity.

Archaeologists also found the remains compacted between layers of pottery fragments and collapsed masonry in two underground chambers, named W2 and W3, that are believed to have previously served as a ceramic workshop.

In addition to confirming historical record of the plague’s spread, the burial site at Jerash provided researchers with insight into the movements of ancient societies.

While historic and genetic data often presents the possibility of large groups moving between regions often, burial evidence often contradicts this, susggesting that communities remained local and did not travel as much as record claims.

The findings at Jerash show that both patterns coexisted, the study explained. Where in times of non-crisis, migration is a slower and more subtle event that takes place over the course of generations, during times of crisis, “individuals from more mobile backgrounds were brought together in one place, making those hidden connections visible,” the study explained.

"By linking biological evidence from the bodies to the archaeological setting, we can see how disease affected real people within their social and environmental context,'' Jiang said. "This helps us understand pandemics in history as lived human health events, not just outbreaks recorded in text.''

"Pandemics aren't just biological events, they're social events, and this study shows how disease intersects with daily life, movement and vulnerability. Because pandemics reveal who is vulnerable and why, those patterns still shape how disease affects societies today.''