Justinianic plague did not wipe out the Romans as history books tell us

By Dr. Ananya Mandal, MDDec 3 2019

A new study has revealed that it was not plague that killed half of the world’s population and thus proved to be the downfall of the Roman Empire as we know from history. The study was published this week in the latest issue of Proceedings of the National Academy of Sciences. The study involved scholars from different fields including history, archaeology and science. The study is titled, “The Justinianic Plague: An inconsequential pandemic?”

The plague that wiped out the Roman Empire is commonly called the Justinianic Plague or JP and is claimed to be a Pandemic. It was named after the Byzantine or Eastern Roman emperor Justinian I. He is said to have caught the plague himself but survived the infection. JP is in fact the first recorded pandemic and is said to have begun and existed between circa 541 and 750 CE. It led to changes in the political milieu as well as the social and economic picture at the time. The Black Death – plague again, had killed half of European population in the Middle Ages and the Justinianic Plague or JP is said to have killed thousands in the Late Antiquity period.

Plague is caused by bacterium Yersinia pestis and authors wrote that there are three plagues in human history that are pandemics and are most infamous. These include the first pandemic or the Justinianic Plague of circa 541 to 544 CE. Then came the second pandemic or the Black Death that affected “western Eurasia and North Africa” after the conclusion of the JP and lasted for around two hundred years. The third plague affected South and East Asia at the beginning of the 20th Century and was also a global pandemic.

Yersinia pestis bacteria. Image Credit: Everett Historical / Shutterstock

Lee Mordechai, a postdoctoral fellow at the University of Maryland's National Socio-Environmental Synthesis Center and first author of the study said, “If this plague was a key moment in human history that killed between a third and half the population of the Mediterranean world in just a few years, as is often claimed, we should have evidence for it -- but our survey of data sets found none.”

For this study a team of researchers looked at not only historical records but also archaeological finds from the time including coins, burial sites, stone carvings, pollen samples and genomes of the isolated microbes from the time. Mordechai, who also leads Princeton's Climate Change and History Research Initiative (CCHRI) jointly, said that over the last couple of decades there has been a great importance placed on this plague and its effect on the Roman Empire.

Results of this study however revealed that the numbers estimated to have died from the plague could be far less than what was believed earlier. This would also mean that the plague was not instrumental in the fall of the Roman Empire said the study. The authors wrote, “Extraordinary claims demand extraordinary evidence. We find little evidential support for the claim that the JP [Justinianic Plague] was a watershed event.”

The team wrote that unlike the Black Death in Europe that resulted in mass graves which were later discovered, there were so such mass burials during the JP. One of the authors of the study, Janet Kay, a lecturer in the Council of the Humanities and History and the CSLA-Cotsen postdoctoral fellow in Late Antiquity at Princeton University, said, “We investigated a large data set of human burials from before and after the plague outbreak, and the plague did not result in a significant change whether people buried the dead alone or with many others.”

Little things pointed at the final picture. For example during the Black Death there was a decrease in the amount of cereal pollen, the evidence of which can be found in peat or lake sediment. During the JP, no similar decrease in noted, they wrote. One of the authors, Adam Izdebski, assistant professor of history at Jagiellonian University in Krakow, Poland, a member of CCHRI and now associated with Max Planck Institute for the Science of Human History, said, “We used pollen evidence to estimate agricultural production, which shows no decrease associable with plague mortality. If there were fewer people working the land, this should have shown up in pollen, but it has failed to so far.”

Based on their results the team also wrote, “...the JP and the so-called “First Pandemic” bear comparatively little resemblance to the Second Pandemic and the Black Death, which significantly affected the demography, economy, and landscape of western Eurasia and North Africa. In light of the paucity of supporting evidence, the “First Pandemic” label is problematic.”

Study coauthor Merle Eisenberg, an environmental historian at the University of Maryland’s National Socio-Environmental Synthesis Center in Annapolis added, “Support for the claim that the Justinianic plague was a watershed event in the ancient world is just not there.” He added, “Our paper rewrites the history of Late Antiquity from an environmental perspective that doesn't assume plague was responsible for changing the world. The paper is notable because historians led this PNAS publication, and we asked historical questions that focused on the potential social and economic effects of plague.” Hendrik Poinar, one of the authors of the study and professor of evolutionary biology and director of the Ancient DNA Centre at McMaster University, explained, “Although tracing the origins and development of the plague bacterium is crucial, the presence of the pathogen does not in itself mean catastrophe.”

Co-author Timothy Newfield, co-lead of the CCHRI and assistant professor of history and biology at Georgetown University said, “While plague studies is an interdisciplinary, demanding field of study, most plague scholars rely solely on the types of evidence they are trained to use. We are the first team to look for the impacts of the first plague pandemic in very diverse datasets. We found no reason to argue that the plague killed tens of millions of people as many have claimed. Plague is often construed as shifting the course of history. It's an easy explanation, too easy. It's essential to establish a causal connection.”

The researchers added however that this was speculation and was not perfect. Mordechai said, “None of the data sets is perfect. But at the moment they are the best thing we have. Future researchers could find different sources of data that disagree with our conclusions.” He added, “It's easy to assume infectious diseases in the past would have catastrophic results. Yet, we used every type of data set we could get our hands on, without assuming a disease outbreak must result in catastrophic results, i.e. that tens of millions died. We found no evidence in any of these data sets to suggest such a destructive outcome.”