A new study suggests that Cleopatra’s defeat was actually caused by environmental reasons due to a volcanic eruption.

Until now it was thought that the defeat of Cleopatra’s and Mark Antony’s forces at the battle of Actium led to their doom and to Egypt becoming a province of the Roman Empire. However, new analysis has shown that it might have been a massive volcanic eruption that disrupted the seasonal flooding of the Nile with devastating consequences for Egyptian agriculture that led to the fall of Cleopatra, about a decade earlier than the battle of Actium.

Researchers collected evidence from ice-core records of eruption dates, which combined with the Islamic Nilometre and study of documents from Ancient Egypt show that a massive volcanic eruption in 44BC might have caused suppression of rainfall. Failure of the floodwaters which would consequently follow might have led to famines, plague and social unrest and Cleopatra’s hold of power would have weakened about a decade before her defeat in 30BC.

The new study focuses on the economy and how the environment had an impact on agriculture rather than the politics and scheming of the Ptolemaic dynasty. The agriculture in Ancient Egypt depended on the annual flood of the Nile. If the flood doesn’t rise high enough, nothing can grow.

The new study has found that a massive volcanic eruption occurred in the world in 44BC. Researchers also found that recent volcanic eruptions strongly affect the Nile flooding, as is evident in data from the Islamic Nilometer, the longest-known annually recorded hydrological record, which started in 622 AD. In addition, references to famines, revolts and the desertion of land in papyrus records show that there is a connection to volcanic eruptions in ice-core data in 209BC and 238BC.

Although there is scepticism towards the new study its authors say that this is a new angle from which to examine history. The findings of the study are published in the journal Nature Communications.