Bioarchaeological signatures during the Plague of Justinian (541–750 CE) in Jerash (ancient Gerasa), Jordan

Jerash (ancient Gerasa, in modern day Jordan) reached its demographic peak in the 3rd century CE with a population of roughly 25,000, but by the end of the 6th century this had declined to about 10,000, setting the stage for the urban vulnerabilities examined in this study. The W2 and W3 chambers of the Jerash hippodrome contain a densely layered mass burial of ∼230 individuals dating to the mid-6th to early 7th century AD. Through archaeological documentation, stable isotope analysis, and ancient DNA study, we present the first biomolecularly confirmed mass grave associated with the First Pandemic (Justinianic Plague) in the Eastern Mediterranean. The taphonomic pattern, rapid, high-density deposition with minimal funerary structuring, closely parallels catastrophic plague pits of the later medieval period, making Jerash a uniquely well-preserved example from Late Antiquity. Stable carbon and nitrogen isotope values from human bone collagen indicate diets dominated by C3 resources typical of the region. In contrast, oxygen isotope values from tooth enamel display a markedly wider range than those documented in long-term residential populations at Tell Dothan, Pella, or Faynan in the Levant. Although oxygen isotopes cannot specify geographic origin, the magnitude of variation, arising within a burial event deposited over only days or weeks, suggests that the individuals interred in the Jerash mass grave grew up in diverse childhood water ecologies. We interpret this pattern conservatively as evidence of heterogeneous lived experiences among the victims during the crisis. Ancient DNA analysis has recently identified a single, uniform strain of Yersinia pestis, confirming a synchronous epidemic event. In this study, mitochondrial haplogroups H13 and L3e were detected among the victims and fall within the expected maternal diversity of the Byzantine Levant. Taken together, the archaeological, isotopic, and genetic results establish Jerash as the earliest securely identified catastrophic plague burial in the Near East. The First Pandemic concentrated a potentially socially and geographically heterogeneous population into a single mortuary event, providing a rare empirical window into mobility, urban life, and vulnerability in Late Antiquity. Jerash thus offers a critical anchor point for reconstructing the demographic and epidemiological landscape of the early medieval Mediterranean.