Did first plague kill half of late Roman Empire? Evidence may be exaggerated, study says

The death toll of the first plague pandemic, credited with wiping out tens of millions of people in the late Roman Empire, may have been exaggerated in past historical accounts, new research suggests.

Anywhere from 25% to 60% of the estimated population is said to have been wiped out by the Justinianic Plague from 541 to 750 CE, but a comprehensive analysis of diverse data sets found little evidence that there was widespread death.

"We're not saying there was no plague. ... It devastated families, ripped apart villages and towns," said study author Merle Eisenberg, a postdoctoral fellow at the University of Maryland's National-Socio Environmental Synthesis Center. "What we are saying is we simply couldn't find demographic, economic and social effects (of mass death)."

Existing research attributes the Justinianic Plague as leading to major social and economic changes in Europe at the time, including the end of the late Roman Empire, the researchers say.

The paper, published Monday in the peer-reviewed Proceedings of the National Academy of Sciences, employed a variety of data to see if there were evidence of mass death in the period.

Pollen data was used to study if agricultural production declined during the period, as would be expected if millions of people were dying, Eisenberg said. Similar data has shown a decline during the Black Death, a plague that swept across Europe in the 1300s, but research did not find similar evidence during the Justinianic Plague period, the paper says.

The researchers also studied legislation and other government indicators during the period. If millions were dying, the government may stop functions, Eisenberg said, but no such evidence existed.

Changes in burial traditions were studied, too. During the Black Death, how people disposed of corpses changed as more people died, said study author Janet Kay in a statement.

"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," she said.

Among the other data used to determine the extent of the death: written sources, inscriptions, coinage, papyrus documents and plague genomes. "We used everything we could possibly think of to ask and answer this question," Eisenberg said.

Plague is a deadly infection caused by the bacterium Yersinia pestis and can spread via rodents, fleas or humans. While plague still exists and infects people around the globe – multiple cases in China were reported last month – modern antibiotics can treat it.

Other recent research has tied Yersinia pestis to three major plague pandemics: the Justinianic Plague, the Black Death and a third that killed millions in Asia at the turn of the 20th century, the paper says.

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Eisenberg says that past estimates of a widespread death toll from the Justinianic Plague largely relied on two written texts from Constantinople, where it is possible an epidemic did take place given that it was an urban center with a large population.

Past research has also extrapolated the percentage of the population loss from the Black Death, when better records were kept, to apply to the Justinianic Plague. "If half the population died, we should see some evidence of that," Eisenberg said.

While the plague may have hit densely populated areas hard, "the idea that it was a blanket catastrophe affecting all parts of the Mediterranean, Middle East and central and western European worlds needs to be rethought," John Haldon, a Princeton University historian of ancient Europe and the Mediterranean, told the magazine Science News. Haldon was not part of the research.

Studying pandemics and deaths can be challenging, and even for modern catastrophes, exact numbers are hard to verify, Eisenberg said. He cited examples of wide-ranging possible death tolls from the earthquake in Haiti in 2010 to Hurricane Maria in Puerto Rico in 2017.

What may have made the Justinianic Plague less fatal than the Black Death is also unknown, Eisenberg said.

What's needed next is research that can give a more accurate estimate on the Justinianic Plague's death toll, he said. That research must rely on a bottom-up approach, where historians study the plague's effects in specific locations to create a patchwork history that tells the larger story.

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