Historians Debate Drought and Rebellion Connections in Roman Britain

Recent studies are sparking debate among researchers regarding whether droughts in late Roman Britain triggered conflicts. While climatologists present evidence linking droughts to civil unrest and violence, historians challenge the accuracy of this interpretation, citing misinterpretations of vital historical documents.

This ongoing debate underscores the complex challenge of integrating historical climate data into the broader historical narrative. “This is a recurring theme,” notes Dagomar DeGroot, a climate historian at Georgetown University in Washington, D.C.

In a recent study, Wolf Bungen and geographers from the University of Cambridge examined tree-ring data from oak trees across southern England and northern France, reconstructing climatic conditions from 288 AD to 2009.

They identified a sequence of intense summer droughts in southern England between 364 and 366 AD, correlating this period with the “Barbarian Conspiracy” of 367 AD—a series of military defeats inflicted on the Roman Empire by British and Irish warriors, including the abduction of high-ranking commanders. Although the Empire eventually reestablished its dominance, it gradually retreated from Britain over the subsequent fifty years. Bungen and his team argue that these droughts caused food shortages, prompting revolts against Roman rule.

Moreover, they extended these findings across the Roman Empire, analyzing 106 battles alongside tree-ring data from Europe, revealing that battles were more frequent following dry summers and extremely hot years.

The implications of this study received significant media attention, with coverage from BBC News, The Guardian, and The Telegraph.

However, a contrasting perspective emerged from another research team in a critical response published in the journal Climate Change. “We believe the issues within this study warrant scrutiny,” remarks Helen Foxhall Forbes, a historian at the Ca’ Foscari University of Venice, Italy.

While acknowledging the intrigue of climate data on historical events, Forbes critiques the interpretations of historical and archaeological references in Bungen’s team’s work.

According to Forbes, the only contemporary account of these conflicts comes from the Roman historian Ammianus Marcellinus, who documented Roman history from 330 to 400 AD, and whose writings on the barbarian uprisings remain fragmented. Her examination of Ammianus’s work concludes that his references to the “barbarica conspiracy” could imply an organized rebellion or simply conflict and unrest.

Furthermore, Forbes points out Ammianus’s description of the British as being in an “Ultimum…Inopium” state—interpreted as complete helplessness—which might allude to starvation or other crises. She argues that Ammianus’s reference to this state is a result rather than a cause of the conspiracy.

Bungen’s team has defended their position in a follow-up publication in Climate Change, highlighting previous research interpretations of Ammianus’s terminology, such as Inopium and barbarica conspiracy.

Another concern raised by critics pertains to the lack of consistency in their battle database, wherein varying types of conflict—from formal battles to civil disturbances—are represented. According to Dan Lawrence, an archaeologist at Durham University, the implications of drought-induced food shortages might incite riots, but solid evidence to support such a narrative is needed.

“The research team lacked a historian on their roster,” states Foxhall-Forbes. Although Bungen’s team included archaeologists, expertise in late Roman Britain was absent.

Bungen has emphasized his commitment to interdisciplinary work, incorporating input from archaeologists specializing in the Roman Empire. He expressed a desire for constructive dialogue and collaboration with researchers who can reinterpret or expand upon their findings. He also noted that frequent research on climate change and history tends to overlook ecologists, who play a pivotal role in understanding agricultural responses to climatic shifts. “This is often where research remains ambiguous,” he remarks.

DeGroot, who did not participate in this review, acknowledges the absence of historical context in this study as a significant shortcoming but maintains that the core findings related to tree-ring data remain valuable for historical inquiries. “We know that the drought likely occurred,” he states. “We can further investigate whether droughts indeed influenced societal violence through case studies.”

DeGroot reflects on the tension between “minimalist” and “maximalist” historical interpretations. Minimalists focus primarily on specific events, often reluctant to generalize, while maximalists strive to identify overarching trends in fragmented data sets. “While they can reveal previously unconsidered forces, often their conclusions may stem from shaky foundations,” he observes.

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