How Volcanoes Helped Rome Conquer Egypt

The volcanic history behind the fall of the Pharaohs

Abstract: Many assume the revolts of Egypt’s Ptolemaic Kingdom were due to ethnic tension. A native uprising to throw off the shackles of Greek oppression and the like. But recent findings suggest that the unrest may have had a deeper cause. A cause far beyond the realm of human control.

Photo by Prof. Mortel

Two historians walk into a faculty party

Francis Ludlow is a climate historian at Trinity College, Dublin. He has studied volcanic activity going as far back as 2,500 years. He’s done this by examining ice-core samples from Greenland and Antarctica. In doing so, he saw strata from sulfate accumulations associated with volcanic eruptions. This gives him intimate familiarity with Earth’s history of volcanic activity.

While doing some post-doc work at Yale, he met Joseph G. Manning, a professor of ancient history. At a faculty party, they got to talking over what Ludlow called “a couple of bottles of wine.” When Manning talked of revolts in Ptolemaic Egypt, alarm bells went off for Ludlow. Every revolt Manning mentioned coincided with a major volcanic eruption. It had to be more than a coincidence.

The troubled Ptolemaic Kingdom

The Ptolemaic Kingdom lasted 275 years from 305–30 BCE. It began in the wake of Alexander the Great’s fabled conquests. The once-mighty Egyptians found themselves under Greek rule. And it wasn’t to their liking.

Earlier, under the Persians, the local officials had for the most part still been Egyptian. But the new Greek government, the Ptolemiac Pharaohs, had a different management style. More hands-on, and more boots on the ground.

Under Hellenic rule, there was a lot of discord. Ethnic tension is the polite way to say it. But to be blunt, it looks as if the Greeks were downright racist.

Think of the Ptolemies as a real-world example of the proverbial alien overlords. Egypt used to rule the known world. In their minds, there was Egypt, then there were the neighboring lands that would soon be Egyptian as well. Part of their ever-expanding empire.

And then the Greeks came in, traversing great distances, to rule over them as if they were a lesser species.

Suffice to say, there were many uprisings and revolts.

So, what’s all this about volcanoes, then?

Pursuing his hunch, Ludlow searched for a causal link between volcanoes and unrest. Eight of the ten biggest revolts of the Ptolemaic Era happened in years of volcanic activity. Something had to be going on.

Searching more modern records, Ludlow found his smoking gun. Or, smoking crater, if you will.

He found that some of the bigger volcanic eruptions in the last 1,100 years coincided with Nile failure. In other words, the river Nile had failed to flood for some reason. Which had devastating repercussions. Agricultural irrigation in the region depended on flood waters.

Ludlow soon developed a model that went like this:

  • A volcano erupts, spewing ash into the air.
  • Some of the ash forms an even blanket in the upper atmosphere before falling back to Earth.
  • The ash reflects back sunlight, thus lowering the average global temperature.
  • The lower temps lead to reduced groundwater evaporation.
  • Reduced evaporation leads to less cloud accumulation.
  • Fewer clouds and cooler temperatures lead to the reduced severity of African monsoons.
  • This leads to less rainfall on Africa’s east coast, the area that feeds the Nile.
  • In turn, the Nile is less likely to flood.
  • And if it doesn’t flood, crop yields suffer. And so do a lot of people.

When crops failed, it’s not surprising to learn the Greeks started hoarding food. In doing so, they left a lot of already angry Egyptians on the brink of starvation. Thereby pushing them to the brink of rebellion.

All this because a volcano on the other side of the world had gone off. A mountain they weren’t even aware of had decided their fate, making a tense situation that much worse.

Hey, let’s talk about Cleopatra for a while

By the reign of Cleopatra VII, Ptolemaic Egypt was already in an uneasy alliance with Rome. It was a partnership forged out of necessity. Teaming up with the Romans helped keep the Seleucid Empire from marching in and taking over.

Cleopatra kept close relations with the Romans. But volcanic activity undermined her reign, with two major eruptions in 46 and 44 BCE. To make matters worse, the latter eruption was the third biggest blast we’ve seen in the last 2,500 years.

She handled the crisis better than most, though. She halted grain exports and opened up national food reserves. Her actions helped feed her subjects. And in doing so, she managed to hold off open rebellion.

But the combined effects of Nile failure, famine and plague were too destabilizing. It made Egypt ripe for annexation.

I should note here that the blast of 44 BCE also lines up with Julius Caesar’s assassination. Rome at the time was dependent on imported Egyptian wheat. It’s curious to see how widespread the effects of Nile failure might have been. Did Cleopatra’s lover get stabbed in the back because his people were going hangry?

It could well have been a mitigating factor.

The Romans have an easier time of it

By comparison, the Romans seemed to have a better time of ruling Egypt than the Greeks ever did. Much less civil unrest and such.

Now, was this a reflection of what the Egyptians thought about the Romans? Did it say something about Rome’s particular brand of imperial rule? Or does this also have something to do with volcanic activity?

While no one has a definitive answer, Ludlow is quick to point out something he calls the Roman Quiet Period. The Ptolemies had to deal with 14 major volcanic events in 275 years. But when Rome took over Egypt they only had to deal with four big blasts over a period of 200 years.

Implications for the present day

We know of the Ptolemies’ vulnerability to Nile failure due to their record keeping. The Ptolemaic Kingdom was one of the best documented periods of ancient history. But the strain of famine was likely felt other places where farmers relied on monsoon rains. Even without written records, other parts of Africa and Asia must have suffered as well. A major volcanic blast can have a devastating global impact.

Today, Nile failure is a worry of the past thanks to the engineering marvel that is the Aswan Dam. But for 70% of the global population, agriculture is still dependent on monsoon rains. The irony of these devastating storms is that they feed billions. Without this much-needed rain, the suffering would be catastrophic.