Following a millennium of unrivalled supremacy in the Mediterranean, the Roman Empire collapsed at the turn of the 4th century AD. To this day, historians have been questioning the motives behind the fall of Rome. What was responsible for its decline? Was it political turmoil? Moral decadence? Barbaric invasions? Short answer: a lot of reasons.
The fall of Rome has been sparking debates among historians for a long time, especially since the 1776 publication of Edward Gibbon’s controversial book, The History of the Decline and Fall of the Roman Empire. “The story of its ruin is simple and obvious, Gibbon wrote; and, instead of inquiring why the Roman empire was destroyed, we should rather be surprised that it had subsisted so long.” Nevertheless, it has been hard to reconcile everybody around the same answer. Some argue that it may be because studying the decline of Rome leads us to contemplate, as in a mirror, the fall of our own civilization… We don’t lack historical answers to that puzzle, though – and are actually spoiled for choices. German historian Alexander Demandt identified more than 200 reasons behind the fall of Rome. What about them?
Cause #1: Climate issues
For more than four centuries, Romans experienced an exceptionally warm and clement climate known as the ‘Roman Climate Optimum’ and roughly running from 250 BC to 200 AD. This was essential to Rome’s growth, mild temperatures (on average 1°C more than today) favouring plentiful crops and full granaries able to fulfil the needs of the Empire’s 40,000-men army and its galloping population. By the mid-2nd century AD – some estimate it may have been later – the trend slowly reversed. The drop in temperature was followed by diluvian rains. The flooded prairies forced nomadic tribes of the Balkan regions, notably Huns, to invade the Western world in search for fresh pasture for their horses (and other riches). In 450 AD, an invasion of mosquitoes plagued the capital city, spreading malaria and reducing the number of available legionaries – which in turn pushed for recruiting Barbarian mercenaries. To cap it all off, a series of volcanic eruptions between 530 and 540 contributed to the overall decrease in temperature (sunlight being unable to filter through the smoke and ash), creating again conditions for starvation and disease.
Cause #2: Epidemics
“All were shuddering, fleeing, shunning the contagion, impiously exposing their own friends, as if with the exclusion of the person who was sure to die of the plague, one could exclude death itself also.” This is how Pontius of Carthage described the Plague of Cyprian, which devastated some areas of the Empire in the 3rd century. Weakening Roman legions, pandemics contributed to destabilising the Empire as a whole, at a time when Roman borders were constantly under threat by Germanic tribes or Persian invasions. The Cyprian Plague was not the first one the Romans had to weather; earlier, between 165 and 180 AD, the Antonine Plague caused 2,000 deaths a day within the walls of Rome. Next was the Plague of Justinian, spreading quickly throughout the Byzantine Empire and killing a fifth of Constantinople’s 6th-century population, no less. Flu, bubonic plague, malaria, filoviruses and smallpox severely damaged Roman administration between the 2nd and the 6th centuries, opening chapters of its irreversible decline.
Cause #3: Migrations
Let it be known: Germanic tribes hoping to cross Roman borders from the 5th century onwards were not only attracted by its many riches. Some foreigners wished to benefit from the local administrative system or the Romans’ lavish lifestyle featuring running water, heating and plumbing systems as well as paved roads. Others simply fled climatic troubles, slavery or war plaguing their home countries. Rome couldn’t care less: in 395 the Empire split up, giving birth to the Western and the Eastern Roman halves. This broken unity was followed by other disasters: ten years later, in 405, Vandals, Suebi and Alans crossed the Rhine River and crossed swords with imperial troops. Rome was sacked in 410, 455 and 472 – worrying signs: “When I heard that the bright light of all the world was quenched, or rather that the Roman Empire had lost its head and that the whole universe had perished in one city, wrote Jerome of Stridon, then indeed, I became dumb and humbled myself and kept silence from good words.” By the early 6th century, the Roman Empire had shrunk noticeably. Franks and Burgundians occupied Gaul, Visigoths had conquered Iberia, Ostrogoths dominated Italy, Vandals mastered Carthage and Slavic tribes fought in the Balkans for what was left of it. The last emperor of Rome, Romulus, was deposed in 476.
Cause #4: Corruption
The divorce between the West and the East proved very costly. Soon the gap between both Empire’s halves was widening, with Byzantium thriving while Rome collapsed. The imperial treasure, usually fed by taxes, military plunders and trade, was suddenly threatened by Barbarian looting, destructions, military overspending, heavy infrastructure-related costs – bridges, roads, aqueducts – and a sharp rise in prices. (The Roman elite was indeed trying to create more money through adding less ‘noble’ metals to the traditional denarii, leading to inflation.) In such an unstable situation, it was necessary to provide the Empire with a steady, organized administration. However, communications were slow, and the cumbersome bureaucracy could not make so many diverse provinces work efficiently together. Corruption, blackmailing and extortions plagued both the Senate and the army: “everything was being torn apart for money,” wrote bishop Ambrose of Milan in the 4th century. As evidence of the general atmosphere of instability and resentment towards the Roman elites, no less than twenty emperors succeeded one another in 75 years… What if the Empire had simply gotten too big and too diverse to run smoothly?
Cause #5: Decadence (?)
It has been argued since the 18th century that the decline and ultimate fall of Rome resulted from the decadence of its people, revelling in debauchery and extravagant pleasures. The 19th and 20th-century paintings of so-called Roman ‘orgies’ bear witness to that fact… or do they? Actually, Roman decadence is a common misconception that does not fit a culture famous for its piety, frugality and self-control. This theory shouldn’t be considered a historical explanation – rather a warning message suffused with Christian values, cautioning people against hubris and sin. “In these latter years wealth has brought avarice in its train, and the unlimited command of pleasure has created in men a passion for ruining themselves and everything else through self-indulgence and licentiousness.” So wrote the Roman historian Livy… in the 1st century AD! That is sufficient proof: people have not waited for the decline of the Empire to guard themselves against overindulgence and debauchery. It was only later that the fall of Roman civilization was used to teach a moral lesson.
Cause #6: Christianity (?)
As with any ‘rupture’ episode in history, the Roman Empire’s troubled years have called for scapegoats. Corrupted or hedonist elites were some of them; emancipated women and recently-freed slaves were others. Christians have also been – falsely – considered responsible for the fall of Rome. The new religion was only authorised in 313, which gave plenty of time for the local authorities to persecute its members. Nero once accused them of spreading the great fire of Rome (64 AD) and had them executed for that. And when the capital city was sacked by Barbarian invaders, in the 5th century, its inhabitants turned against their Christian counterparts, arguing that the new faith had turned the city’s guardian gods away… Tenants of the new religion were also blamed because they would not attend the bloody shows featured in the amphitheatres, or because their churches cost the taxpayers too much. Should we then consider Christianity a contributing factor to the collapse of Rome? Somehow, the new religion added colour to Roman values, and while emperors used to be considered deities, they weren’t anymore at the advent of the one-and-only, supreme God. Change happened, indeed. However, Christianity was no brutal cultural earthquake. Its advancement within Roman paganism was slow, seeping through Roman society from the 1st century AD on, making plenty of room for the locals to adapt. If they couldn’t, it was mostly because Rome was already on the verge of collapse, undermined by military, economic and political distress.
What if Rome had survived?
Investigating the main causes behind the fall of Rome, one is faced with an obvious conclusion: not one isolated historical fact could be considered major contributor to its collapse. It is rather a myriad of causes, all mixed up and linked together – bad harvests triggered civil unrest, massive emigration entailed cultural shifts – that led Rome towards its downfall. When precisely? As soon as the divorce between East and West was approved, in 395? When Rome fell by the Visigoths’ sword in 410? When its last emperor was deposed in 476? Hard to say: because the fall of Rome was not a sudden fracture but, instead, a transition towards another era, introducing chapter of the Middle Ages. By the way, did Rome really fall? The Byzantine Empire, its Eastern half, held steady until 1453. The Holy Roman Empire constituted a model of political unity from Charlemagne to Napoleon. In other words, Rome’s legacy remains intact – and the Eternal City proved worthy of its nickname for, 1,500 years later, it is still not done falling.
- Kyle Harper, “How Climate Change and Plague Helped Bring Down the Roman Empire”, Smithsonian Magazine, 19 décembre 2017.
- McCormick, Michael et al. “Climate Change during and after the Roman Empire: Reconstructing the Past from Scientific and Historical Evidence”, The Journal of Interdisciplinary History, vol. 43, no. 2, The MIT Press, 2012, pp. 169–220.
- Caroline Wazer, “The Plagues That Might Have Brought Down the Roman Empire”, The Atlantic, 16 mars 2016.
- Ramsay MacMullen, Corruption and the Decline of Rome, Yale University Press, 1988.
- Nelville Morley, “Decadence as a Theory of History”, New Literary History, vol. 35, no. 4, Johns Hopkins University Press, 2004, pp. 573–85.
- Xavier Darcos, « Une parabole : la décadence romaine », Revue des Deux Mondes, février-mars 2019.
- Louis C. West, “The Economic Collapse of the Roman Empire”, The Classical Journal, vol. 28, no. 2, The Classical Association of the Middle West and South, 1932, pp. 96–106.
- Eric H. Cline, Trois pierres c’est un mur… Une histoire de l’archéologie, CNRS, 2018.