It is 94 AD, in the Colosseum of Ancient Rome, and thirty men have been condemned to die. Thousands of rowdy, cheering onlookers are there to witness their executions. The men, malnourished and with cuts and bruises still healing from rough treatment by their gaolers, are completely naked, jeered at spitefully by the crowd. Each man has his hands tied behind his back. Each man is strapped to one end of a petaurum [pet-tar-um] – a long plank of wood resting on a fulcrum, much like modern seesaws, but long enough to raise a man 5 meters into the air. In happier circumstances, these devices would be used by acrobats who would jump and tumble off of them, performing innocent stunts for an appreciative crowd and polite applause. But today the giant seesaws have a much more sinister purpose.
Suddenly there is a loud groan of scraping wood and the clanking of chains. Twenty lions are raised through the floor by an elaborate network of elevators dotting the arena. They have been deliberately kept hungry for this very moment. The lions pause briefly, sniff the air, lay eyes on vulnerable prey, and, with a mighty roar, charge forward.
The panicked prisoners watch the beasts approach and in a flash the lions are upon them. The men at the bottom leap out of harm’s way, rising high into the air, safe for a moment from the mauling and mutilation that would almost certainly result if they had remained on the ground. But this temporary respite comes at a cost. The men at the other end of each petaurum are helplessly lowered toward the ground and the ravenous beasts below. Exposed limbs, torsos, faces, and genitals are torn to shreds by razor sharp claws and fangs. The lucky ones receive a swift bite on the neck and are killed quickly, while the others are ripped, torn, and gradually devoured while they are still alive and screaming.
Some of the men, blind with fear, leap into the air, sending their opposite number on the seesaw back toward the ground again. The frenzied lions tear into them. At the earliest possible moment, every man who is still alive leaps off the ground as soon as their feet touch it. The whole thing becomes a perverse game of seeing who will die last. But death is inevitable for everyone involved.
In this way, the Romans have forced the prisoners to take part in each other’s executions. Each attempt at escape coming at the expense of the life and suffering of another man. Meanwhile the crowd cheers, eats, and laughs at the suffering and humiliation of the prisoners. And they make bets on the gruesome spectacle unfolding before them, as the arena becomes splattered with 150 litres of blood.
This is just one instance, among a legion of examples, of the brutal acts committed by the Romans for centuries. Inspiring some of the cruellest villains of fiction, the Romans were callous and sadistic even by ancient standards. While many valid cultural, philosophical, and religious explanations exist for Roman brutality, there is one further component that might be overlooked – there was something in the water.
This is the story of how lead-poisoning may have transformed the elite of Ancient Rome into a gang of callous psychopaths, and a story that leads us to one of the most controversial and hotly debated theories about the decline and fall of the Roman Empire.
Brutal executions were commonplace throughout the ancient world. What is notable about Roman punishments is the degree of psychological sadism that was often involved.
Another mode of Roman execution was being sewn into a leather bag and thrown into a river. Alongside you, the sack would contain a dog, a snake, a rooster, sometimes a rat, and possibly even a monkey if there was one available. As you all drowned, the animals would attack and bite each other, and bite you a hundred times over. Drowning might be bad enough, but as the water seeped in through the leather and the poor stitching at the top of the bag, for over several long minutes as you ran out of air and the water filled your lungs, you’d be assaulted on all sides. Drowned twice. Drowned in water. And drowned in a downpour of teeth, scratching claws, and an overwhelming sense of doom and dread. You’d die in pain and panic. You’d die in darkness. Exactly as the Romans meant for you to die.
The same psychological cruelty applies to crucifixion. While 2000 years of religious symbolism has desensitized us to crucifixion somewhat, make no mistake that this was a form of horrific death inflicted by the Romans to be slow and agonizing. And public. The grim display was meant to cause maximum suffering in the victim and to strike fear into the hearts of any criminals or rebels who would dare oppose the majesty of the Roman order.
You’d be whipped, paraded through the streets, and have your hands and feet nailed to a few pieces of lumber. Depending on how long they wanted you to suffer, supports could be built into the cross to hold you up and prevent a quick asphyxiation. The position with which you were held on the cross could also vary. Some people would be crucified upside down, others would be nailed to the cross by their genitals. Women might be crucified with their faces, breasts, and private parts against the wood of the cross to “preserve their modesty”. As the Romans dropped your cross into a peg-hole in the ground, the sound of your cries of agony from the cross’s thudding impact with the soil was part of the show for the crowd. You were meant to scream.
And you’d be left there. To starve, to suffer, to bake under the Sun, to die of a heart attack, of exhaustion, of dehydration, of asphyxiation, and all within plain view of the populace. It was a ritual humiliation. This was an expensive and inefficient form of execution, but it was spite that inspired Roman crucifixions, in the most venomous sense of the word. Oftentimes, prisoners would be forced to carry their cross (weighing more than they did) to their site of execution. After a war or rebellion, the Romans often took special care to line the hills with as many crucifixes as they could to make sure they were sending a clear message. Sometimes in the hundreds, sometimes in the thousands. Notably, after Spartacus’s rebellion some 6000 people were ordered to be crucified. But the punishment was also used against soldiers for dereliction of duty and even generals who failed spectacularly in military campaigns.
While crucifixions did occur in the ancient world before Rome, they were far less common, and many ancient cultures, including the Ancient Greeks, generally rejected crucifixions in most cases as being too cruel and barbaric. It was the Romans who elevated the practice to almost industrialised scales.
Today, the brutal realities of crucifixion have faded somewhat in modern minds. But to the earliest Christians– living nearly two thousand years ago, for whom crucifixion was not just an archaic practice but a living threat – it was a powerful symbol that entirely reflected the horror and suffering that was imposed on tens of thousands of people (messiah or otherwise) at the whim and will of Rome.
Rome shocked even the ancient world with its capacity for genocide. When Julius Caesar conquered Gaul (which is roughly modern day France and Belgium) between 58 and 50 BC, he is said to have killed up to one third of the population, either by direct military violence or by starvation from scorched Earth tactics. Another third of the Gallic population was enslaved. Only a final third of Gaul’s population survived to live as free men under Roman colonial subjugation. The pre-Roman population of Gaul is estimated to have been 5 to 10 million people. Around 90% of people killed in the Gallic Wars were not soldiers in the field. And all told, Caesar’s war in Gaul killed or enslaved around 2% of the world’s population at the time.
That is quite the price for one man’s quest for glory and notoriety. In fact, many of Caesar’s various campaigns against Gallic tribes were based on the flimsiest of justifications. A fact that did not go unnoticed in Rome. While Caesar’s own political faction may have applauded his conquest of a long-standing enemy and threat, and the Roman populace at large appreciated Caesar’s daring and the plunder he sent back into Italy, large sections of the Roman Senate decried Caesar’s brutality toward Gallic non-combatants, women, and children, in what they deemed to be a decade of illegal warfare.
Worse still was the fate of Carthage, over a century earlier. When the Romans won the Third Punic War, they did not just seek to humble, humiliate, and punish the Carthaginians. The Romans sought to wipe them from existence. Well known is the Roman destruction of the city of Carthage in modern day Tunisia. As is the salting of the Earth around the city from which the Romans had hoped their enemies could never grow crops ever again. But the Romans also annihilated Carthaginian history. Documents and culture were deliberately destroyed. As far as the Romans were concerned, if history ever heard about Carthage, it would be a Roman who told their version of the story. Even today it is a challenge for archaeologists and ancient historians to reconstruct the Carthaginian past without depending on highly biased Roman accounts. In short, this was not just a war between two Mediterranean rivals. It was a war that ended in cultural genocide. And there was no question that it was deliberately done.
A Culture of Callousness
Beyond the torture of prisoners and the overall Roman body-count from war, there is the overall spite and callousness that seemed to permeate every facet of Roman culture.
Military discipline, in the days of the Roman Republic especially, was sometimes maintained with the practice of decimation, where one tenth of every Roman cohort was chosen by lottery for execution – regardless of what those individuals had or hadn’t done. They would be stabbed or bludgeoned to death by their comrades. The idea was to inspire fear and obedience in the rest of the Roman army.
When it came to public entertainments, Cicero once wrote to a friend in disgust that he had witnessed a Roman crowd throw a man to be devoured by animals, not because he had committed any crime, but because the crowd had thought he was extremely ugly. Similarly Caligula was said to throw merchants to the beasts for raising the prices on sweet-meats, or to kill criminals by sacrificing them to the beasts regardless of the nature of their crimes – theft, murder, or petty vandalism – simply because there was a shortage of victims. He is even rumoured to have once turned the animals on part of the crowd.
Even in times of national celebration, Roman cruelty was not far off. A Roman triumph, which was a parade to celebrate military victories, would frequently be ended by watching the leader of an enemy nation be strangled to death in full public view and in front of Rome’s most sacred of religious temples. Such was the fate of Vercingetorix, leader of a Gallic revolt against Caesar, who was kept alive in prison for six years just so he could take part in this macabre ceremony. And such likely would have been the fate of Cleopatra had she not killed herself before the Romans could capture her and transport her back to Rome.
The Roman practice of proscription, undertaken by the military dictator Sulla, and again later by the Second Triumvirate of Octavian, Marc Antony, and Lepidus [Lep-pid-us], confiscated the property of hundreds (if not thousands) of Roman citizens and placed the threat of death over their heads. By declaring these people enemies of the state, and encouraging Roman citizens to kill them if they were able, the Roman government was able to eliminate its political enemies without formal trials – instead just by drawing up a list. The Roman government would also deprive the families of the proscribed of any property and any inheritance, coldly acquiring the lands and funds for itself. Some historians theorise that many such victims may have been targeted not for their political affiliations, but just because adding them to the lists may have fattened Roman coffers. Even when it came to political enemies, Romans were often calculatingly cruel. Marc Antony’s sworn enemy, Marcus Tullius Cicero, found himself upon these lists and, in yet another characteristic act of Roman brutality, the great orator had his hands and tongue nailed to the doors of the Roman Senate. Octavian, who had benefitted from Cicero’s help in his own early rise to power, and had no love for Antony, simply and coldly allowed this to happen.
As Rome transitioned from a republic to a military dictatorship, an endless stream of assassinations and executions increasingly permeated political life. There are too many to list here. From the many unnecessary executions carried out by emperors Tiberius, Caligula, and Nero, to the opportunistic and jaded military contest between Roman elites in the Year of the Five Emperors, to the many palace coups that did not shy away from the murder of children, Roman politics were ultimately cynical and quite frequently founded on “might makes right” rather than any of the higher civilised ideals touted by Roman writers. This culture of cruelty at the very top persisted for half a millennia in the Roman West.
There were many sources of Roman brutality. For instance, Roman religion permeated every aspect of society, including government. And the gods of the Roman religion were capricious and cruel. They often had moral compasses the equal to, or worse than, the humans who worshipped them. For this, one need look no far than Saturn, who castrated his own father in a bid for power, and in order to safeguard his own rule, systematically devoured his own children.
The worship of gods, who could be unjustifiably cruel or mete out terrible punishments at the slightest sign of displeasure, was much more common across pre-Christian Roman culture than the notions of dignitas and the tradition of Roman honour and magnanimity studied by the elite. And as republic shifted toward empire, the most powerful figures of the Roman elite increasingly came to resemble and imitate those capricious gods in their actions. And, more than once, they were officially elevated to the status of gods themselves. It is easy to forget that this was, after all, a highly religious pre-modern society.
The Romans inherited much of their Pantheon from the Greeks, after the Roman conquest in 146 BC. However, from what we know of the Roman gods before this date, they appear to have been similar in their brutal and oftentimes animalistic character. Of course, the Romans also inherited the more sober-minded philosophies of the Greeks, and these philosophies often paired well with the Roman ideal of dignitas. Thus even within Roman society there was an perpetual tension between notions of Roman justice, liberty, and honourable behaviour, so often the subject of Roman literature, and the stark, sadistic realities that seemed to appear at every level of society. Roman moralists consistently decried this sadism and yet it seems to have been an inextricable part of Roman life for many centuries.
In many ways, early Christianity was a reaction against this “might makes right” aspect of Roman culture, finding favour among the Roman Empire’s most downtrodden slaves and freemen. Indeed when Christianity was adopted as the official religion of the Roman Empire in the fourth century AD, gladiatorial games and executions by being thrown to beasts were phased out, and crucifixions were abolished as a form of punishment. However, many other brutal practices of Roman culture were far too entrenched to be expunged, and remained in place until the fall of the empire in the West. In some cases, they remained entrenched in Europe until modernity.
It is also quite possible that Roman brutality may have a simpler sociopolitical explanation. The Roman Republic came to dominate the Mediterranean by being more ruthless than its ancient rivals – who were by no means full of sweetness and light. For example, archaeology has recently confirmed that the Carthaginians did indeed practice child sacrifice. And when it came to the many deeds committed by the Romans that seemed to contradict its earliest laws and central morals, one can perhaps attribute that to the increasing corruption of the Roman Republic and the moral decay of many centuries of military dictatorship in the Roman Empire that gradually began to look increasingly like a despotic monarchy again. Studies of 19th and 20th century military dictatorships seem to bear this out. When constitutional safeguards are overthrown by force, every level of society begins to eat itself as laws and social conventions are flouted, eroded, and brought down in a game of “every man for himself”.
We do not need to do away with any such explanations. But there is one strange chemical phenomenon that may have made the problem even worse.
The Roman world was a technologically advanced society that in many was not surpassed until just a few centuries ago. From the first aqueduct to bring water into the heart of Rome in 312 BC, came a system of plumbing that brought water into houses, tenant blocks, and multi-storey apartment buildings. And the practice was gradually transplanted to every major city in the empire. These systems of plumbing would outlast even the final Western Roman emperors and gradually fall into disrepair and disuse in the 500s AD. And similar systems of indoor plumbing would not be seen again in common use throughout Europe until over a thousand years later.
There was just one problem. The pipes which carried this water were typically made of lead.
Today, we know that lead is toxic when ingested by humans, resulting in lead-poisoning that is harmful to both the body and the mind. Even in Ancient Rome, scholars had some idea that ingesting water from lead negatively affected one’s health, though they could not work out the science of precisely how. The Romans correctly deduced that consuming water from clay pots and earthen pipes was healthier than from receptacles made from lead, but the knowledge appears to not have been widely known, nor did most people who lived in cities have much choice when it came to their day-to-day water use.
That is not to say that the dosages of lead-poisoning that hit the Romans were anywhere close to fatal. Usually, the water flowed in from rivers to the city, via the aqueducts and lead pipes, into fountains, troughs, and sinks without many taps or spigots to control waterflow. As such, the amount of time water remained in the lead pipes was limited, reducing the amount of lead that could be picked up by the water and transferred to thirsty Roman mouths. Furthermore, gradually these pipes could sometimes form a hard layer of calcium carbonate, which further insulated the water from lead contamination.
Unfortunately, everyday consumption and use of water from these pipes seems to have carried with it a sustained and lifelong exposure to small amounts of lead. Every day Romans would drink, wash, and rinse their food with water. Not all pipes had a large amount of calcium buildup, pipes were sometimes replaced, and some water spent more time within the plumbing system and carried more toxins with it. At the very least, consuming water from these sources, which millions of people did over hundreds of years, increased the risk of lead-poisoning if you were to drink water in a Roman city. The phenomenon was at the very least common enough to be noticed and recorded by Roman scholars.
Furthermore, in 2014 French researchers found that lead levels in Roman pipes would have been at least a hundred times higher than in surrounding spring waters. Still not high enough to be deadly, but enough to create above average levels in the human body. And in 2019 a study of skeletons from Roman era London found that lead levels were 20 to 40 times higher than in pre-Roman skeletons, which almost certainly would have been enough to start making a noticeable difference to people’s health, perhaps even causing serious maladies.
Added to this, lead pots were often used to contain and cook food, particularly in wealthier households – poorer people often used copper pots. Lead was sometimes used as a food preservative as well. Powdered lead, or lead acetate, was used as a fortifier in various medicines and as a sweetener in Roman wines. One teaspoon of this wine sweetener had enough lead in it to start doing kidney and liver damage. And some Roman aristocrats may have ingested half a litre to two litres of sweet wine every day. The Romans also made use of lead in cosmetics (along with a range of other noxious chemicals including arsenic) which would have been absorbed through the skin.
Add all this to regular, if minor, exposure to lead in water, and the picture is clear. A wealthy Roman elite, and Roman city-dwellers, rich and poor alike, had a much greater likelihood of lead-poisoning than their lower class compatriots in the countryside, who lacked indoor plumbing and the temptations of sweet wines, and perhaps didn’t have the money or time to faff about with makeup.
Lead can enter the human body by eating it or inhaling it, and can even enter the body through contact with the eyes or by absorption through the skin. Therefore drinking it, eating food washed in contaminated water, or even washing oneself in tainted water, would have been a possible cause of lead-poisoning in Ancient Rome.
When lead is absorbed, our bodies don’t really know what to do with it. So our bodies store it in our bones, blood, brain, kidneys, liver, and lungs. But lead has no real function in the human body. And while it is stored, it interferes with an abundance of basic cellular, respiratory, and neurological functions.
If you are dosed with one single amount of lead in a large quantity, your body could go numb, you could suffer splitting headaches, have an increased heart rate, anxiety, and you could become physically weak while you vomit, experience diarrhea and/or constipation, undergo rapid weight loss, suffer liver and kidney damage, urinate blood, and ultimately you could go into shock and die. There was probably not enough lead in Roman water to start causing citizens to suddenly drop dead.
But exposure to milder amounts of lead-poisoning over a longer period of time, as the Romans likely were, results in sensitivity in the joints and extremities (which Romans may have mistaken for gout), indigestion, trouble sleeping, stupor, slurred speech, blurred vision, and swelling of the brain. The neurological effects could be personality changes, irritability, delirium, depression, apathy, if not seizures and increased risk of a coma. Up to 25 Roman emperors, and a large number of Roman consuls, generals, senators, and aristocrats, for whom we have adequate biographical descriptions, display physical symptoms or behavioural traits that could be consistent with lead-poisoning. This list includes Julius Caesar, with his brutal behaviour and possibly his propensity toward seizures (though he also could have been epileptic), Caligula, with his sudden murderous personality change after a period of illness, and even the emperor Claudius, with his numerous physical and intellectual maladies that closely fit the profile of lead-poisoning.
The impact of lead-poisoning is even more pronounced in children, who absorb up to five times more lead into their bodies from exposure sites than adults do. Lead-poisoning can also devastate a still-developing brain. Bear in mind that urban-dwelling and also elite Roman citizens would have been raised in cities from birth. Smaller amounts of lead in the water, in food containers, and in various wines and medicines, which an adult could withstand, could do long and lasting damage to a Roman child. If lead is stored within a child’s bones, brain, liver, or kidneys, it can remain in the body for decades into adulthood. And Roman children would have grown up being exposed to all of these sources over many centuries in both the Republic and Empire.
Lead-poisoning in children has been linked with aggressive behaviours and severe developmental disorders. It can start as a greater proneness to attention deficit disorders and a lower IQ, but can develop into impulsive and violent behaviours, anti-social withdrawal, cruelty to animals, outbursts of anger, lack of empathy for others, and a fair helping of traits typically associated with sociopathy and psychopathy.
In the 20th and 21st centuries, numerous studies linked lead-exposure in childhood to adult criminal violent behaviour, and a greater likelihood toward substance abuse and an inability to maintain stable relationships. Furthermore, the elimination of lead in paints, manufactured products, petrol [gasoline?], and plumbing from the 1970s onward has been linked by some experts as one factor among many others to the overall decline in the crime rates in developed nations from the 1990s onward.
While the connection between childhood lead-poisoning and future criminality can be overstated – there are hundreds of potential causes from congenital mental illness, to rates of poverty, to abusive or absent parents, to the trauma of sexual abuse – there is little question that elevated levels of lead exposure in childhood drastically increase the risks of developmental disorders occurring in young people at an extremely formative age. Export this risk to society at large, and you might see a cultural impact at the macro-scale.
Take an entire generation of Roman elites and city-dwellers. Dose them with regular amounts of lead-poisoning as children. Watch their developmental problems blossom into full blown personality disorders. Continue to dose them with lead-poisoning when they are adults. And get them to raise yet another generation of children who also are exposed to lead-poisoning. Eventually you create a multi-generational culture of badly-adapted adults who might be more prone to acts of violence, gruesome torture, callous disregard for human life, and impulsive despotic behaviours that seem to violate basic human decency.
In a word, you might get a culture where it is considered an appropriate form of mass entertainment to strap prisoners to seesaws and watch them get torn to pieces by lions. Put these same people in charge of the government of one of the mightiest superpowers of the Mediterranean world, and run the experiment for nearly eight centuries. What you might wind up with is Ancient Rome.
Most intriguingly, sustained lifelong lead-poisoning would have been a phenomenon of Roman cities and landed estates. So it is possible that this neurological damage may only have been done to city-dwellers and the Roman elite. If so, the unusual levels of cruelty would have been imposed by the wealthy and the so-called civilised members of the empire upon rural subject peoples and peasant farmers in the countryside, or 65-85% of the Roman population who did not have regular exposure to lead pipes and indoor plumbing. If the smallfolk of the empire on average had more balanced mental health, and fewer childhood developmental disorders, then the cruelty visited upon them by Rome may have seemed almost as shocking as it would to more modern observers today.
And bear in mind, in a pre-modern Europe 300 or 500 years ago, where life was in many ways still cheap and public executions were still an entertaining town spectacle, accounts of Roman cruelty in rediscovered Latin literature seemed shocking even to them.
Combine the possible neurological and psychological damage done by lead-poisoning to generations of the empire’s elite with religious mythology, laws, and culture that seemed to accentuate brutality and cruelty, and it is hardly a surprise that the Romans have the reputation that they do.
Fall of the Roman Empire?
As with any plausible theory, some people like to take things to the extremes. First proposed by Rudolf Kolbert in 1909 and revived by Jerome Nriagu in 1983, in the middle of the US campaign to get lead out of people’s homes, some scientists and historical theorists have asserted that the mental disorders brought on by lead-poisoning may have brought down the Roman Empire itself. This theory has been widely rejected by ancient historians as an oversimplification based on some fairly spurious connections.
The crux of the theory goes that exposure of the Roman elite to lead-poisoning resulted in generations of maddened and erratic rulers than there would be otherwise, which in turn lead to periods of immense instability like the Third Century Crisis, from which the Western Empire arguably never fully recovered.
Firstly, given the number of contending theories out there that claim to explain the decline of the Roman West – from technological stagnation, to population pressures, to disease, to famines, to the decoupling of Roman citizenship from military service, to the increase of Germanic incursions driven forth by the Huns – it really does not pay to pin the fall of the Roman Empire on one cause. A phenomenon known in historical work as “mono-causality”.
Secondly, the endless civil wars, place coups, and Roman infighting in the third century, the late fourth century, and the fifth century certainly did the empire no favours. But erratic rulers, vain contests for power, and poor government aren’t confined to cultures that may or may not have problems with chronic lead-poisoning. One can find incompetent, maddened, and power-hungry elites on almost every page of history.
Thirdly, if lead-poisoning was a problem for the Romans, then it was already present in Roman society in the first and second century AD, when the Roman Empire was at its height. And for several hundred years beforehand as Roman power grew across the Mediterranean. In short, if lead-poisoning made large numbers of Romans act like psychopaths, there were many centuries where that worked for them.
Fourth, a large and popular school in ancient history that has been around for several decades disputes the idea of a cut-and-dry “fall” of the Roman West altogether, which they say oversimplifies a complex series of more gradual transformations that occurred in the fifth and sixth centuries AD. Others maintain that the transformation of former Roman villas into cowsheds and the disappearance of many useful technologies from Europe for several hundred years indicates some sort of severe decline and probably wasn’t just a “cultural choice” within the new Germanic kingdoms. But that is an entirely different – and massive – historiographical debate.
Fifth, a large number of historians point out (correctly) that the Romans were well aware of the negative health effects of lead exposure, and scholars such as Vitruvius [Vit-true-vee-us] counselled people to avoid using lead wherever possible. Other historians contend that while the Romans may have been aware of acute lead-poisoning, there isn’t actually a reference to chronic lead-poisoning in writing until the seventh century AD, long after the last Western Roman Emperor was overthrown and Rome’s aqueducts had fallen into disrepair.
Sixth, since 1983, ancient historians opposed to the theory have maintained that lead-poisoning was not even a problem in Ancient Rome. It is only more recent paleopathology in the past decade showing skeletons with high levels of lead that hints, for city-dwellers at least, lead-poisoning was a very real risk, if not a chronic problem endemic to Roman cities. Further studies of this sort in the coming years may resolve just how widespread the problem of chronic lead-poisoning actually was.
A Lead-Based Diet?
The decline of the Roman West in the fifth century was the perfect storm of so many factors that had been building for centuries, that it was most likely beyond any Roman emperor, general, or aristocrat’s power to reverse the tides of failure. Whether their mind was addled by lead-poisoning or not. That theory seems to be, for most historians, a bridge too far. It is more the stuff of sensationalist news headlines invoking the popular idea of a “mysterious fall” of the Roman Empire, than of serious scholarship.
However, the more moderate question of whether numerous generations of Roman city-dwellers and elites suffered from mild lead-poisoning, which in turn may have contorted their mental stability in childhood remains open. It is an idea supported by the most recent archaeological findings of the past few years. It is also supported by decades of modern medical examination of the link between lead exposure and developmental disorders in childhood and the likelihood of criminal behaviours in adulthood.
Thus combined with religious, cultural, and political factors in Ancient Rome – along with the fact that the ancient Mediterranean world in general was often not very nice place to be – a seemingly insignificant metal contained in the local plumbing and the household crockery, may well have contributed to why, for centuries, a large number of Romans behaved like such utter dicks.
The debate will rage for a few more years to come, but if there is any moral to this story it is this: when you move into a new house, please make sure your plumbing is up to code. Especially if you have a young family. Especially if, for some ungodly reason, you have nicknamed one of your children “Little Boots” or, in Latin, “Caligula”. Once every two thousand years with someone like him is, I think, probably enough.