The Fate of Rome
Climate, Disease, and the End of an Empire
By Kyle Harper
Category: History | Reading Duration: 20 min | Rating: 4.4/5 (523 ratings)
About the Book
Over the years, countless historians have theorized about the causes of the fall of the Roman Empire. The Fate of Rome (2017) tells this story from a slightly different angle, taking into consideration new information about the climate and epidemiological events that played a major role in the prosperity and downfall of one of the largest empires in history.
Who Should Read This?
- Roman history enthusiasts
- Environmentalists and others interested in climate change
- Anyone curious about the causes of the Roman Empire’s fall
What’s in it for me? Learn how nature played a role in the rise and fall of the Roman Empire.
Often, we think of history as a kind of neverending story advanced by human leaders both great and terrible. What we don’t consider is just how great a role nature plays in that story. In recent years scientists have grown ever more interested in the climate records that lie hidden within nature – inside tree rings, glaciers, caves, and even human remains. The unintended beneficiaries of this knowledge are historians, who now have a much better understanding of how our world looked and felt in the past.
As it turns out, the rise and fall of the Roman Empire coincided with a particularly fateful sliver of our planet’s climate history – for better and for worse. We can’t attribute Rome’s success or its decline to nature alone. But we can’t discount the role nature played, either. As you’ll see in this summary, Roman history is utterly inextricable from environmental history.
In this summary, you’ll learn - how the Romans won the climate lottery;
- why the Romans were short; and
- what caused a year without summer.
Chapter 1: An unusually favorable climate contributed to the Roman Empire’s prosperity.
Life in the Roman Empire, even when that empire was flourishing, was rough. Infant mortality rates were high. Life expectancy, in general, was only around 25 years. There were no motorized vehicles or telecommunications devices, so travel and communication were incredibly slow.
Despite these limitations, the Romans were able to form a unified empire that stretched across Western Europe, North Africa, and Western Asia. As the empire and the cities within it expanded and the population exploded, the Romans were forced to extract more and more resources from the surrounding environment. Yet they never experienced a major food shortage, nor were they forced to farm on hard or difficult soil in desperation. Why? Well, in part, the Romans got lucky: they happened to be living in a particularly hospitable moment in Earth’s climate history. The key message here is: An unusually favorable climate contributed to the Roman Empire’s prosperity.
By the second century AD, the Roman Empire had slowed its expansion and achieved widespread peace across its vast territory. For the most part, conditions were very good: economic productivity was high, there was enough food for everyone, and wages were growing even for the most unskilled laborers. Rome’s expansion and flourishing were linked to a climate regime known as Roman Climate Optimum, or RCO. Characterized by a stable, warm, and wet climate, the RCO began in the last two centuries BC and stretched into the first two centuries AD. During the RCO, the sun warmed the earth more than usual – temperatures during the first century AD were even higher than those in the last 150 years of our own era. At the same time, volcanic activity was almost absent.
This meant that the period saw none of the lower temperatures caused when volcanic ash blocks the sun. These conditions were huge boons for the Roman Empire. Thanks to the warm and wet climate, farmers could cultivate wheat and olives on mountains – territory where they could never grow today! North Africa was exceptionally fertile, providing grain for huge swaths of the empire.
By contrast, today, that region is a major importer rather than an exporter of grain. Climate conditions helped Rome to prosper. But that prosperity came at a cost: the Roman Empire’s large number of trade routes and high connectedness created a perfect breeding ground for infectious diseases.
Chapter 2: Disease and ill health were always part of Roman life.
Around the world, populations vary greatly in their average height. Why is that so? Well, one major contributing factor is nutrition. The modern era has seen several nations undergo massive growth spurts thanks to economic development and the resulting nutritional boost.
Just take the Dutch, whose men stood at an average of 164-5 centimeters in 1850. Today, they’re almost 20 centimeters taller on average. As for the Romans? By any metric, they were short, with men an average of 164 centimeters tall and women 152 centimeters. Both pre- and post-Roman Italians were taller than the Romans themselves. Yet Romans’ diets were generally good, with even those on the lower rungs of the social ladder eating height-boosting animal and marine protein.
That meant their small stature was probably caused not by poor diet, but by disease. The key message here is: Disease and ill health were always part of Roman life. The same conditions that helped the Roman Empire to prosper also allowed bacteria and viruses to spread uninhibited. Cities were densely packed and well-connected, via roads and maritime trade routes, so diseases could travel easily from one population to another. Not only could infectious diseases quickly diffuse across the Empire, but Rome’s cities were horrendously dirty. This made them great petri dishes for intestinal parasites.
Aqueducts regularly brought fresh water in and out of cities. Not only did this process provide drinking and bathing water, it also helped to flush out the cities’ sewer systems. However, waste disposal left much to be desired; domestic toilets often didn’t connect to public sewer lines, so most Romans still used chamber pots or open-pit toilets. Human feces were also traded to farmers as valuable fertilizer. All this exposure to human excrement meant Romans were probably often beset by parasites like roundworm and tapeworm. When it comes to the other major killers at the time, the seasonal pattern of death in the Roman Empire gives us some clues.
For all Romans, the deadliest time of year was late summer into early fall – the period in which foodborne stomach and intestinal diseases like typhoid and dysentery thrive. For elderly people specifically, winter was deadliest, since elderly bodies are most susceptible to respiratory infections. The Romans were never truly healthy. But things were far, far worse than usual when a new disease appeared on the scene to devastate the population: the Antonine Plague.
Chapter 3: The Antonine Plague triggered an economic crisis in the Roman Empire.
There is perhaps no environment that mosquitos love more than the swamp, a large body of standing water filled with tall grasses. And it just so happens that Rome, the city at the center of the vast Roman Empire, was built upon this kind of wetland. Not only was Rome surrounded by swamp, but the city itself was full of waterworks like decorative fountains, pools, and urban gardens – ample breeding ground for mosquitoes. Now, mosquitos are annoying.
Worse than that, though, they carry a host of deadly diseases. For Rome, the greatest mosquito-borne killer was malaria. But even this malnutrition and fever-causing disease paled in comparison to the destruction caused by the Antonine Plague, an epidemiological event that brought the empire to its knees. The key message here is: The Antonine Plague triggered an economic crisis in the Roman Empire. According to one Roman legend, the Antonine Plague was released during the Roman sack of the Mesopotamian city of Seleucia, when a soldier unsealed a chest inside a sacred temple of Apollo. Inside the chest, they said, lurked a pestilential vapor that snaked its way out and pervaded the empire.
Of course, we now know that the plague – which was probably the disease we now know as smallpox – existed inside the empire well before the day when the “noxious vapors” were supposedly released. It took hold in the City of Rome in AD 166, and it continued its devastation for at least 8 years. Rome’s organized health care system, which included basic nursing, probably softened the plague’s blow. But still, its impacts were devastating. Determining the exact death toll from a plague that happened so long ago is difficult, but estimates of the death toll range from 2 percent of the population to an entire third. The military was hit particularly hard by the disease, and the emperor Marcus Aurelius noted that slaves, gladiators, and brigands had to be quickly conscripted to help replenish army ranks.
At the same time, in the late AD 160s, imperial silver mining, which allowed the Empire to consistently produce more coins, suddenly collapsed. An economic crisis ensued. With so much of the population depleted, demand for land decreased at the same time as its monetary value sharply declined. Labor was scarcer, and productivity losses were considerable.
Ultimately, the Antonine Plague wasn’t a fatal blow to the Roman Empire. But it did damage the system, making it less resilient in the face of other threats to come. The City of Rome, AD 248. At first glance, the city looks much the same as it did a generation ago, at the height of its glory.
Chapter 4: In the third century, the Roman Empire experienced its first fall.
But upon closer inspection, things seem less opulent, less prosperous, and generally less stable than before. For starters, the coins circulating within the city, once solid silver, are little more than metal wafers with a thin wash of silver to coat them. Stone fortifications now surround the city, protecting against outside forces. An obscure cult known as Christianity is just showing signs of gaining footing.
Rome is in the midst of its “first fall. ” The roots of the crisis lie in a devastating drought, a new pandemic, and barbarian invasions. The key message here is: In the third century, the Roman Empire experienced its first fall. Let’s rewind four years. In AD 244, an aristocrat named Philip became Emperor of Rome. His reign brought stability at first – but not for long.
Over the next few years, the empire was beset by both internal rebellions and barbarian intrusions across the river Danube and in the East. Philip was killed in AD 248, and for the next two decades, one usurper after another would attempt to take the throne. At the same time, the days of the Roman Climate Optimum were drawing to a close and the climate regime known as the Late Roman Transition was just beginning. This period brought with it diminished solar activity, and cold began to set in. Glaciers in the Alps crept back after centuries of melting. A deep drought struck North Africa and Palestine.
Finally, weak or nonexistent Nile River floods denied the region the water and silts it needed for grain production. The empire was struggling – which meant it was wholly unprepared to deal with another plague event that started in AD 249 and lasted for 13 years: the Plague of Cyprian. Witness testimony claimed that the disease, which may have been caused by a filovirus similar to Ebola, carried off at least 5,000 souls per day. By the AD 260s, the empire had fractured into parts. The silver content of the Roman currency continued to plummet, destabilizing its value. The prices of goods wildly oscillated as a result.
The combination of military loss, coin debasement, and imperial fragmentation inspired the assassination of the emperor, Gallienus, in AD 268. Luckily, his successor, Claudius II, picked up the pieces. His reign ushered in an age of recovery that allowed the empire to flourish once again.
Chapter 5: The Roman Empire rebuilt after the first fall, but it didn’t last.
In the late third and fourth centuries, the Roman Empire was still the most powerful empire in the world. A series of reforms occurred throughout this period. They included those of the emperor Diocletian, who established the tetrarchy, giving four separate rulers the power to manage the sprawling empire. The army was rebuilt, and currency stabilized too, allowing markets to regenerate.
After Diocletian came Constantine, the son of a military officer. A controversial figure, Constantine set up a second senate in the empire’s eastern capital, Constantinople. In less than a century, the population of the city grew tenfold, from 30,000 to 300,000 residents. The empire was in the midst of a new golden age – but the peace wouldn’t last forever. The key message here is: The Roman Empire rebuilt after the first fall, but it didn’t last. Emperor Constantine’s reign brought stability to the empire.
These stable conditions were mirrored in the environment. The climate was generally warm, rains were reliable, and the empire was spared major disease events and volcanic activity. But globally, things weren’t quite as peachy. In particular, the Eurasian steppe, which stretches from Central Europe into East Asia, was experiencing major aridity. This led to food shortages and famine. Combined with rising political tensions, this led to an age of migrations from Asia into the West.
One group that migrated in the mid to late 300s was a nomadic tribe known as the Huns. The Huns’ ferocity as warriors, along with their superior weaponry, overwhelmed the people living in the western part of the steppe, who were known as Goths. In AD 376, the Huns’ continued migration pushed upwards of 100,000 Goths into the Roman Empire as refugees. The Romans didn’t take kindly to the Gothic refugees. Roman cruelty, which included forcing parents to sell their children in exchange for dogs to eat, led to a Goth revolt. A battle at Adrianople on August 9, AD 378 saw the worst military loss in Roman history: it’s estimated that 20,000 men were killed.
The army never recovered. Soon, the western Roman Empire fell. It happened in two waves. The first began in 405, when a series of destabilizing Goth attacks culminated in the sack of the City of Rome. The second wave came when the Huns, led by Attila, invaded Gaul and Italy in the AD 450s. By AD 476, the western Roman Empire had ceased to exist – yet the eastern Empire still prospered.
Chapter 6: Bubonic plague dealt the first of two fatal blows to the eastern Roman Empire.
In the fifth and sixth centuries, the Roman Empire’s eastern capital of Constantinople was a global hub – a trade center and major city in which you could hear ten or more languages being spoken on the streets at any given time. And sharing this diverse city with its human inhabitants was a species known as Rattus rattus: the black rat. These rats weren’t just annoying pests – they were hosts for a vicious killer we now know as the Black Death, or bubonic plague. The medieval Black Death, which ravaged Europe in the fourteenth and fifteenth centuries, is history’s most famous occurrence of bubonic plague.
But its first appearance came in AD 541, when it arrived on the shores of Egypt and ravaged the Roman Empire. The key message here is: Bubonic plague dealt the first of two fatal blows to the eastern Roman Empire. The black rat is a Southeast Asian native. But these rodents love to travel, and they love grain even more. That meant they were all too willing to hitch a ride on Roman ships in the Red Sea and Indian Ocean. The rats themselves weren’t the source of the plague.
The culprit was a bacteria called Yersinia pestis. Most of the time, Y. pestis lives within a host population of rodents, usually marmots or gerbils. It spreads when fleas ingest blood from an infected rodent and transmit it to a rat population. The bacteria sickens the rats and causes their population to dwindle, depleting the fleas’ food source. The fleas then switch to a diet of human blood as a last resort.
Bubonic plague is an exceptionally fatal disease, especially in a world without healthcare or antibiotic treatments. Prior to the plague, the population of Constantinople was thought to be half a million. Primary sources claim the death toll in the city was 300,000 – in other words, 50 to 60 percent of the city’s population. The plague raged across the Empire in fits and starts for two centuries, from AD 541 to AD 749. It was aided by frigid climate conditions perfect for the spread of the disease – and perfect for dealing the final blow to an already-stressed Roman Empire.
Chapter 7: The Roman Empire never recovered from the Late Antique Little Ice Age.
The Black Death wasn’t the only deadly and seemingly apocalyptic event gripping the faltering Roman Empire during the fifth and sixth centuries. In AD 535, a volcano exploded, belching out clouds of ash and smoke. Its eruption caused what came to be known as the year without summer. Witnesses claimed the sun rarely shone, and that when it did, its light was dim and murky.
That was just one instance in a larger chain of climate anomalies. AD 540 to 541 saw another volcanic winter. And the AD 530s and 540s were the coldest decades of the epoch. In AD 536, summer temperatures in Europe dropped by an entire 2. 5 degrees Celsius – an astonishing figure. This climate era was known as the Late Antique Little Ice Age, and along with the bubonic plague, it helped push the Roman Empire toward its final collapse.
The key message here is: The Roman Empire never recovered from the Late Antique Little Ice Age. The lack of summer in AD 536 meant major crop failure. Fortunately, though, the previous year had seen a bountiful harvest, and the grain stores were plentiful enough that the population inside the empire came out of the shortage relatively unscathed. But there were famines elsewhere, in Ireland and China – a testament to the worldwide scale of the climate changes. The frigid temperatures also resulted in major demographic decline – as few as 10 to 20,000 people may have called Rome their home at this time. Entire settlements appeared to shrivel up.
Various Gothic tribes spread throughout Spain, Gaul, and Italy. The wild began to grow back over the farmland that had once fed the empire’s great western cities. In the east, the army had been stretched thin by the devastating effects of the plague. The state couldn’t pay its soldiers’ wages, and so couldn’t muster enough troops to defend the imperial territory. The armies of the neighboring Persian Empire took the city of Alexandria in 641. With the Persian victory, all grain shipments to Constantinople stopped for good.
Over the following years, the plague strangled the last gasps of life out of Constantinople, and the emperor Heraclius presided over the empire’s final failure in the early AD 640s. The Arabs – Christian, Jewish, and Islamic – seized the former jewels of the Roman Empire in the east and the south. The city of Constaninople struggled on, but the Roman Empire had well and truly collapsed.
Final summary
The key message in this summary: Thanks to recent scientific investigations into natural climate records, we now know more than ever about the environmental conditions that existed across the wide expanse of the Roman Empire. The Roman Climate Optimum coincided with the height of the empire’s prosperity, but this naturally warm and wet period ended in AD 150, ushering in a period of climate instability combined with major plague events. The Late Antique Little Ice Age and bubonic plague put major stresses on an empire already fractured and stressed by war and invasion, and by the early AD 600s, almost all of its territories had fallen to the Arab caliphate.
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About the Author
Kyle Harper is a scholar of Roman history who currently serves as Professor of Classics and Letters at the University of Oklahoma, where he is also Senior Vice President and Provost. He has written two other award-winning books: Slavery in the Late Roman World, AD 275–425, and From Shame to Sin: The Christian Transformation of Sexual Morality.