Why the Roman Republic fell | Results

Gregory Néméc

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It was early spring, 43 BCE, and Roman soldiers ate tree roots and bark to ward off hunger. They cooked animals “never tasted by men”, according to Plutarch. Eighteen months later, food shortages persisted. Antoine wrote to Cleopatra asking for grain, but she could not help, she said. She had her own famine to deal with.

The supplies were undoubtedly suffering from the recent assassination of Julius Caesar and the violent disintegration of the Roman Republic. But a new document in the Proceedings of the National Academy of Sciences suggests that the cataclysmic eruption of a volcano 6,000 miles away could also have been a factor.

A group of researchers have linked traces of volcanic ash in ice cores from Greenland and Russia to Mount Okmok, a volcano in the Aleutian Islands. With unprecedented precision, they dated the ashes of two consecutive eruptions: a minor in 45 BCE and one in 43 BCE which is one of the largest in recorded history. The researchers used simulations to model the potential effects of the eruption in the Mediterranean. They saw a drop in average seasonal temperatures of up to 13 degrees Fahrenheit, as well as disturbances from the East African monsoon, which produces the Nile floodwater essential for agriculture.

“It was a time when the Mediterranean region was in full transition,” said Joseph Manning, professor of history at Yale and co-author of the article. The Roman generals fought for power; Egypt’s long-standing Ptolemaic dynasty was embroiled in the war and slipped from power. “And then there’s this huge eruption that seems to impact the climate for a decade – boom, now deal with that.”

Manning aims to write a historical narrative that integrates all the factors. “Politics, economics and military might are important, but nature has a say in this story too.”

David C. Barham