ANNAPOLIS, MARYLAND—Environmental historians Lee Mordechai and Merle Eisenberg of the University of Maryland argue that the outbreak of bubonic plague during the reign of Roman Emperor Justinian in the mid-sixth century A.D. was not a catastrophic event across the Mediterranean region, according to a Science News report. Historians have long blamed the Justinianic plague outbreak as a contributing factor in the decline of the Roman Empire. But Mordechai and his colleagues cite historical texts and archaeological evidence—including a lack of increase in the number of mass graves, the continued cultivation of farmland near eastern Mediterranean trade routes, few plague references in historical texts and stone inscriptions, and stable coin circulation during the sixth century—as support for the idea that the outbreak of disease had a modest impact on social structure. Additionally, samples of the Yersinia pestis bacteria obtained from sixth century skeletons have not been found to be ancestral to the strain of Y. pestis responsible for the devastation of the Black Death in the fourteenth century. To read about an earlier form of the Y. pestis bacterium that was circulating almost 4,000 years ago, go to "Bronze Age Plague," one of ARCHAEOLOGY's Top 10 Discoveries of 2018.