Has the Black Death’s Impact Been Overstated? New Medieval Data Complicates Understanding 

Throughout the past year, Timothy Newfield, an environmental historian and historical epidemiologist, has worked as part of an international, interdisciplinary team studying perhaps the most significant pandemic in human history. No, not that pandemic. Newfield and his co-researchers examined the bubonic plague pandemic of the 14th century, also known as the Black Death. 

The team’s findings, published in Nature Ecology & Evolution, suggest that the Black Death may not have been as uniformly devastating as once thought. 

Finding New Data for a Medieval Problem 

For years, the best sources for understanding the plague have been contemporaneous writers, who documented its impact on their communities. By taking these sources, and assuming a similar effect in other regions, historians have long estimated that Europe’s population was decimated by 40-to-60%. Given the sporadic availability of data, that estimate has never been iron-clad. 

Newfield and his co-authors tackled the question of the plague’s impact by finding a new source of information – medieval pollen samples. Analyzing sediment cores that are dated to the 14th century gives researchers a sense of how land use was impacted by the plague. Pollen can show, for example, a decrease or abandonment in agricultural production. It can also show the continued cultivation of crops in areas where the plague’s devastation was less severe. 

For a more comprehensive dataset, researchers collected pollen from 261 sites across 19 modern-day European countries. The team’s findings, as a result, are not only less biased than personal reports of the pandemic, but they don’t require any extrapolation. 

“This study shows that human landscapes everywhere did not significantly change, let alone collapse, in the immediate wake of the Black Death,” says Newfield. “In some regions, labor-intensive land use systems remained in place; in other regions, they expanded; in others yet, they collapsed. The impact of the pandemic varied region to region.”

By sourcing new data, researchers were able to provide fresh insight on ancient questions, testing hypotheses that, up until now, have only been talked about in theory. 

Teaching the Interdisciplinary Approach 

For Newfield, who teaches courses in both the Department of History and the Department of Biology, leveraging an interdisciplinary approach to tackle historical questions is nothing new. 

His previous work has run the gamut from the Justinianic plague to the origins of smallpox to the consequences of large volcanic eruptions on weather patterns and human societies. Newfield’s recent articles touch on a number of topics, including premodern bovine plagues and the evolutionary history of the measles and rinderpest viruses. With every work, Newfield aims to increase accuracy by tapping into other academic approaches and data – and, he underscores, by building collaborations capable of tackling topics that demand an interdisciplinary approach.

At Georgetown, Newfield is part of a cadre of four historians who run the HyperHistory Hub, a project of the Georgetown Humanities Initiative. The Hub offers history students a chance to hone their science skills through courses focused specifically on what the sciences can teach us about the past. These courses are taught by Newfield, Kathryn de Luna, Dagomar Degroot and John McNeill. Undergraduate and graduate students alike are taught how to tap into interdisciplinary skills like palynology, the study of pollen grains and other spores, to solve historical problems. 

“My work in historical epidemiology is often interdisciplinary, but this is my first large-scale engagement with palynology,” Newfield says. “I often look to combine complementary datasets from different fields to improve our understanding of past disease – and not over-privilege written sources.”

-by Hayden Frye (C’17)