Kyle Harper (7:50)

By those enthroned on high.

Tristan Hughes (7:52)

So Ammianus later, the soldiers searching the temple found a narrow hole. And when this was opened, in the hope of finding something of value in.

Professor Kyle Harper (8:01)

It, from some deep gulf issued a.

Tristan Hughes (8:04)

Pestilence loaded with the force of incurable disease, which in time polluted the whole world, from the borders of Persia to the Rhine and corrupted Gaul with contagion and death. Apollo, a God renowned for his vengeful fancies, did not take kindly to being scorned. And these Roman soldiers, seeking to line their pockets with sacred gold, were the unwitting instruments of his revenge. As punishment for their hubris, they unleashed a pestilence that crept like a shadow across the Roman world. Or so the story spread. The truth veiled by the relentless march of time remains elusive. Did the shadow of plague truly stalk the footsteps of Roman legions returning from distant lands? Or was it a tale conjured up in the corridors of power to smear the general in command of the Parthian campaign? Perhaps we will never know. Equally difficult to discern is the extent to which these diseases helped hasten Rome's eventual fall. Did plague help destroy the very fabric of the Roman Empire? Was it simply one piece of a larger, far more complex puzzle? To help answer these questions, I'm thrilled to be joined by Professor Kyle Harper from the University of Oklahoma. Kyle is a specialist in the ways nature has shaped humanity and is the author of the critically acclaimed book, the Fate of Climate, Disease and the End of an Empire. Kyle Great to have you with us.

Professor Kyle Harper (9:33)

Thanks, Tristan. It's a pleasure to be here.

Kyle Harper (9:36)

Now, when talking about the fall of Rome, I must admit, immediately I do think of either barbarians, the sacks of Rome, or maybe financial problems, disease and environmental stress isn't always at the center, at the forefront when discussing the fall of Rome, when perhaps it should be. Why is that?

Professor Kyle Harper (9:52)

We're familiar with the human factors. It's easy for us to relate to, and I'll be the first to insist that the human factors are enormously important, from the character of individual leaders to the sort of random fate of individual battles that can really turn the course of history one way or the other. So to me, it's not an either or. Those factors are really important. They still matter. But I think we now have new insights, new data, new ways of thinking about the past that previous generations of historians didn't have. And one of the really important and exciting things that these new kinds of archives have told us is that the environment in which human societies operate is a really important factor. And climate change changes, sudden changes in health, in the arrival of infectious disease, of pandemics, have had also a really significant effect on the course of human history.

Kyle Harper (10:51)

You mentioned new data there. So is this almost a new frontier? As these new scientific developments have emerged, people like yourself are learning more through this particular lens of understanding how it goes alongside those human impacts. As you say, in big events like.

Professor Kyle Harper (11:07)

The fall of Rome, there's no single technology or innovation that's really responsible. In fact, you could trace the way that archeology for the last several generations has been really empowered by laboratory science, by radiocarbon, by chemistry. But over the last 20 years or so, there have been, I would say, two really important changes. One is the proliferation of paleoclimate data. This is driven by the urgency of understanding the Earth system, understanding its history, so that we can understand the dynamics of anthropogenic warming. And for historians, it's really exciting because it tells us things that we absolutely didn't know before about the climate context in which these societies operated. The other that's been, I mean, I would say revolutionary is gene sequencing, and in particular, the kind of what are called high throughput gene sequencing technologies that make it fast and relatively affordable to sequence huge amounts of DNA, DNA from people's bones that can tell us about their ancestry, but also at times about the identity of the pathogens that infected them and made them sick. So the rise of these new genetic technologies, which really are new, it's only 15 years ago now that the first complete ancient human genome was published. So this is new, and for historians, this is really exciting. It's telling us about human population history, it's telling us about animal history, and it's telling us about microbe history.

Kyle Harper (12:48)

But does that mean then. So this study of these genetics can help us learn more about ancient pandemics, including those that affected the Roman Empire?

Professor Kyle Harper (12:56)

Yeah, absolutely. So a lot of diseases are caused by infectious agents. Those are infectious diseases because something invades your body and causes the infection. And those are little organisms, they're usually bacteria or viruses. And those little organisms have genetic codes, so RNA or DNA. And under the right circumstances, it takes a little bit of luck. Bacteria are easier to find than viruses. There are DNA viruses and RNA viruses. RNA viruses are like measles, is very, very hard to recover. But with the right pathogen and the right circumstances of preservation, it's sometimes possible to get the DNA of the microbe that killed a specific individual at a specific point in time. And that has really, really revolutionized what we know about the past of human health, of pandemics.

Kyle Harper (13:55)

We've got a few pandemics to get through. But before we do that, is it important to highlight straight away how even these great periods of time in Roman history when there aren't these pandemics, that disease is rife? This isn't a place where everyday health is really, really high. For the Romans, right?

Professor Kyle Harper (14:11)

Exactly. And I think it's very easy for us to forget how radically population level human health has been transformed over the last century and a half. And this transition has revolutionized everything about our world. It's prolonged life expectancies by two to three times. So in the Roman world, we don't know. And there's probably not one stable number. But if I want to pin down a number, life expectancy at birth is probably something like 25 years, plus or minus a few years. A lot of that's infant mortality, a lot of it's childhood mortality. But all the same, the average life expectancy is so much worse in the pre modern period than the modern period. There's several variables that account for that. The most fundamental one is that they don't have modern science. So we are lucky to benefit from modern science, which helps us understand the body, helps us understand the infectious cause of infectious diseases, helps us develop things like vaccines, hygiene, water treatment, antibiotics, other pharmaceuticals. None of those are available in the Roman world. And consequently most people, even in a good year, most people die of infectious causes. So they die of, frankly, of diarrhea, probably the Largest category of infectious disease in the pre modern world is probably diarrhea. I'm not talking about a tummy ache, I'm talking about dysentery. We take for granted a world where you can drink a cup of water and not think twice about whether putting your life in danger. But that's really recent. We have water treatment we know to keep human waste matter and contamination apart from the drinking supply. But in pre modern contexts they didn't have germ theory. They thought of disease as, as a miasma and they were constantly threatened by infectious pathogens that cause dysentery, infectious diseases that cause respiratory illness and so on.

Kyle Harper (16:08)

Yet despite all that, Kyle, it's quite interesting that for the, let's say the first two centuries A.D. or at least to the mid second century A.D. when you've got the beginning of the Roman Empire and some of its most famous names, Trajan, Hadrian and so on, despite this background of poor health, not having the modern science of we do today, there aren't any pandemics during that period. Is that quite surprising?

Professor Kyle Harper (16:34)

It's a good question and I think we can, I don't have a totally clear answer to that. An epidemic is one of these things. It's a scientific term. It actually is just a rough and ready term. There's no minimum number of people that have to die to make it an epidemic. It just kind of means an outbreak of disease in a population. And in ancient Rome, one out of every 10 years must have really stood out, right, where just conditions align. There's a bad harvest and there's a bad strain of something. So epidemics are really bad years. But even epidemics are kind of normal. A pandemic is something else. It's where you have a really big inter regional outbreak of disease. So people are dying in Alexandria, people are dying in Rome, people are dying in Athens, all at the same time. And those seem to have a kind of big bad cause behind them. So most of the pandemics we can understand historically are a sort of fateful alignment of really bad conditions. So sometimes it's not just that there's a food shortage, it's that there's nothing to eat, that there's a real harvest failure that causes a real famine and, or, and usually there's this conjunction of food shortage and virulence. But one of the things that seems to lie behind these rare events that happen every century or two is there is a big bad microbe. There's plague, there's smallpox, there's typhus, there's one of these. There's, there's certain diseases that are just nastier than others, and then there's this like elite class of nightmare germs that seem capable of causing just a different level of destruction. And so we don't totally understand this. This is like a incredibly interesting and rich area of research that combines biology, that combines history and arche. And we really are trying to understand what causes these really, really big pandemic events. It does often seem to be an alignment between a lot of things going wrong at the same time.

Kyle Harper (18:38)

Because I've got in my notes for the 1st century and early 2nd century AD a time period known as the Roman Warm Period. Did that kind of suggest a more stable climate at that time, which helped it when there were cases of epidemics, but that they didn't go from epidemic to pandemic. So that stable climate to ensure that there wasn't that almost perfect storm of problems that would ultimately contribute to a pandemic.

Professor Kyle Harper (19:03)

Exactly. I mean, that's a hypothesis and I think it's one that's pretty persuasive and has some strong evidence behind it. Start with the Roman Warm Period, or sometimes it's increasingly called the Roman Climate Optimum, which is a name for a climate period that maybe goes from like the Late Republic to the apex. The Pax Romana, the first and second century is a name for this climate period that was created by the climate people, not by the Roman history people who are sitting there looking at tree rings and ice cores and observe that in a number of different paleoclimate records that there's a pretty long phase of three, four centuries where it's relatively stable, where there's relatively few major forcing events. And we can maybe come back to what causes climate variability. Climate forcing mechanisms do, and these include, among other things, volcanic eruptions, which are a very powerful short term mechanism of climate change. And they're really interesting in lots of different ways. They're interesting historically, they're interesting for understanding the Earth system and how the climate system works. But volcanoes are this really powerful thing, and I don't mean like the Iceland volcano that sort of dribbles out smoke and disrupt some air travel, as significant as that is every century or two. Even Vesuvius that erupts in the 1st century and buries Pompeii. And Herculaneum is not a big eruption. It's really big if you're in Pompeii and you're broiled to death. But it doesn't cause the global climate system to wobble. Whereas the big eruptions of 536 and 540, in this Roman climate optimum period, you have three or four centuries where there's only one really, really big eruption and it's in the, the sort of aligned with the death of Julius Caesar. One doesn't cause the other. Unless you're like a polytheist and think that Vulcan was mad about the, the assassination or something. It's just pure coincidence. You have this really long phase where you don't have big volcanic eruptions where it looks really relatively stable. It is warmer in core parts of the Mediterranean. And so you do have this kind of background of stability which arguably creates a kind of condition of favorable climate, of prosperity, of agricultural productivity. This is a farming society. Even in the Roman world, 80% of people at least are working in agriculture. And so they're very dependent on the immediate climate context. It has to be warm enough for the growing season to enable crop growth and has to be wet enough but not too warm and not too wet. And so the Roman climate optimum seems to be this phase where you have a relatively stable climate, which probably means a relatively stable food supply, which probably means a population that's relatively able to contend by pre modern standards with the, the pool of infectious diseases that are out there. And then there may be elements of luck. I mean this is one of the things that's most fascinating about this is that history involves, you know, you've got to be lucky and good if you want to build a stable empire. And there is just this pure element of contingency of luck that comes into history.

Jim (22:33)

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Professor Kyle Harper (24:15)

And we're back, folks. It looks like Jim from sales just got in from his client lunch and he's got receipts.

Jim (24:21)

His next meeting is in two minutes and the team is asking, can he get through his expenses in that time?

Professor Kyle Harper (24:27)

He's going for it.

Jim (24:27)

Is that his phone?

Professor Kyle Harper (24:28)

He's snapping a pic. He's texting. Ramp Jim is fast, but this is unheard of. That's it. He's done it. It's unbelievable.

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Kyle Harper (25:00)

Well, certainly isn't it when you think of the big names around the end of the first century and beginning of the second century A.D. with the Romans like Trajan and Hadrian and as you say, that context of they were lucky to live in the time that they did. And it contributes to us, well, historians remembering this time as more stable than others in Roman history. And it seems like Kyle, later in that century, this is when we get, I mean, the first of the big events that we're going to be talking about. Because what happens around the mid second century that is this major disease event that really starts to stir up big problems for the Romans.

Professor Kyle Harper (25:38)

Well, again, to go back to our very first line of conversation, it's always both the human and the natural. So there are really important human factors. There's important things going on inside Roman society, inside the way the empire works, inside the relation between the center and the periphery, between elites and workers, geopolitically, between the Romans and the peoples across their frontier, especially across the northern frontier. So the only question is whether those are sufficient to explain what happens. Because it's not like the Romans had never faced civil conflict the first century. They absolutely do. I mean, in 68, 69, the empire breaks down. The system for controlling power totally melts down. And yet, you know, the empire doesn't fall apart. It doesn't split into permanent pieces. It pretty quickly heals. So there's always.

Kyle Harper (26:34)

That was The Year of the Four Emperors.

Professor Kyle Harper (26:36)

Wasn't it the year of the Four Emperors after the forced suicide of Nero, where there's no script for how you change dynasties and it's settled by force. And these kinds of conflicts are sort of, at some level, always there. But you could definitely argue in the second century that there are new kinds of pressures, particularly geopolitically. But now I think we know enough to say that there are strong clues that we ought to consider the contribution of other factors as well. So two things that I would submit we ought to think about. One is that over the second century, it's now really beyond question that the climate becomes more unstable. Doesn't mean it's necessarily going from good to bad. It's not quite that simple. But it's going from relatively good and relatively stable to more unstable and probably more challenging if you're a farmer in core regions of the Roman Empire, like Italy. And so the hydroclimate, the sort of rainfall patterns, which are really important for farming, they're also really complicated and they're always kind of variable and on the edge in the Mediterranean, where it's arid, where water scarcity is a sort of constant concern for farmers. But in the mid to late second century, the indications are that the climate just starts to wobble more. And I think that there's probably food shortage, even if it's not quite outright famine in the way we might see later. And that's now attested in tree rings in Marine Corps, to some extent in ice cores, where we do see volcanic eruptions becoming a factor again. So this particularly is building over the decades leading into the reign of Marcus Aurelius. But then from the 160s and 170s, it seems to become more acute simultaneously. So leave aside any causal links, but just observing that at the same time, in the 160s, there's a pandemic just unambiguously, for the first time in centuries. There are dozens of indications from all corners of the empire that simultaneously there's an outbreak of infectious disease that people perceive as something different. So it's not just sort of the ordinary background stew of diseases. It's not even sort of the ordinary. Just a bad year, right? The Romans, again, they have bad years. There are epidemics every 10 years, every 5, 10, 20 years. There's sort of, you know, there's dying. That's the nature of the world. In a society where infectious diseases are dominant, this stands out. This is absolutely different in the written record. You have people from all different, you know, different languages, different IDEOLOGIES different genres, who talk about what we call the Antonine plague. So the Antonine dynasty is in power, and we call it the plague. Plague is a really bad term for it. Actually. Plague is kind of an annoying word in English because it's ambiguous. Plague can either just mean pandemic or outbreak of disease or pestilence. The plague also sometimes implies the specific disease of bubonic plague. The plague, the disease that caused the Black Death, the disease that caused the Justinianic plague. It's caused by a specific bacterium called Yersinia pestis. It's totally fascinating bacterium. But the antonine plague is not the plague. It's just we should call it the Antonine pestilence. But we don't think it was caused by the plague, the bubonic plague. It's not totally impossible. And like, we should always have a little skepticism in our mind about how much we know about these ancient pandemics. But we don't think it was the plague. So we should call it the Antonine pestilence. And whatever caused it, it was highly alarming to people all over the empire who describe significant mortality. And this is a society where they're used to a lot of people dying. And this stands out somehow to their experience, to their background. So simultaneously, you've got the human things going on. So you have tribes across the Rhine and Danube that seem to be sort of coalescing into bigger confederations that are more capable of confronting the Roman frontier defenses in an organized and dangerous way. If you're a Roman, that is, of course, going to put pressure throughout the system, because the Roman frontier system isn't designed as a wall. It's designed as a kind of hegemonic zone where the Romans can optimize the threat of what's really not a huge, huge army relative to the territory size. Soldiers are expensive. Somebody's got to pay for them. Somebody is provincial farmers. So if you've got more geopolitical pressure, you need more troops. And if you need more troops, you're going to have to recruit them from farms. You're going to have to pay them more. And that certainly is what happens in the second half of the second century, is they have to pay the army more. They have to raise taxes to do it. So these human factors start to reverberate throughout the system. But now we see that's not all that's going on. So while they're struggling as a system to maintain the dominance that they have, as the price of that goes up, as that's felt on the ground by taxpayers and farmers. At the same time, you have a disease that's killing more people and you have a climate that's making it harder to grow wheat. And it's the concatenation of those factors that makes the second century different. So there'd been dynastic upheaval, civil war before, but now you have it in a context where you have all of these pressures at the same time.

Kyle Harper (32:47)

Is it a theory by the Roman writers that it was brought into the central Mediterranean from the east?

Professor Kyle Harper (32:53)

This is a really interesting and still a little bit open question. We're always interested in where do pandemics come from? We've seen in our own worlds how political and tricky those kinds of questions can be, and it's really not so different. The Romans are curious, where does this come from? They tend to perceive disease through different lenses, often at the same time, religiously. So pestilence is sent by the gods, usually by the God Apollo, and he's mad because the Romans aren't showing sufficient respect. They aren't keeping the peace with the gods. Maybe it's Christians that are upsetting the gods. We can throw a few of them to the lions and see if that will stop the plague. They also think of it in terms of pollution. So I mentioned miasma, this idea that the air can be corrupted and the pollution can sort of spread through the air. They don't have our sense of germ theory, but we do have contemporary and later sources that reflect different beliefs about where this plague comes from. And clearly one of the hypothesis that gets thrown around in the Roman world is that it comes back from Parthia with the armies of Avidius Cassius and Lucius Verus, who are coming back from the east, in my view. And it's like, look at Covid. We have millions of brilliant scientists and there's still honest disagreement about the origins of the virus. In the ancient world, we have only a handful of sources. Many of them are indirect or come from later versions of the story. In a world where they don't understand infectious disease. So it's very hard to actually piece together, and it's made more difficult by the fact that we don't know what the pathogen was. It's super frustrating for me, for a lot of us who work on this period, we want to know what caused this pestilence. And trust me, we're looking like the we collectively, including myself, like we are trying to find bones. If you have a mass grave, if you're listening to this and you have a bunch of skeletons from the second century, Call me. People have looked, we've looked, and we may find out. We may get a hit in the lab. But there's not a huge number of really obvious second century mass graves. That's part of the problem. So there's not a ton to work with. And it may be a pathogen. It takes a lot of luck to get the DNA of pathogens. It has to be present in the blood in high concentration. When the person dies, their body has to be preserved in a burial environment where the DNA doesn't degrade too much, and it has to be a pathogen whose DNA you can get. So if it's a single stranded RNA virus, there's a very good chance we'll never get it. So without knowing what disease it was, you can't say very much about the evolutionary history of it. You can't say this probably came from this evolutionary family tree. So it's a little bit hard to root. But I do think that it's quite possible that the perception that the army is spreading the disease reflects some kind of genuine observation that at the very least, armies concentrate lots of people, they move around. And so even if there's probably a little bit of invective like this is probably a way of criticizing the memory of Avidius Cassius, who later revolts against Marcus Aurelius and goes down in the annals of history as a bastard bad guy. So I'm a little bit skeptical about some elements of it, but probably the Roman army catches this contagion and when it demobilizes after the campaigns in Parthia, is a vector for the transmission of the disease to other provinces of the Roman Empire.

Kyle Harper (37:10)

It's an interesting case, isn't it, the Antonine plague, if you're lacking the bones from that time period, but yet you have the accounts, and yet you need to be careful when looking at the accounts to consider the agendas. But regardless, to have figures like, I think, Galen as well, isn't it who's documenting it? It's an extraordinary time period and extraordinary pandemic to learn about. Carl. If we move on roughly 100 years to the next big pandemic event, which seems to hit the Romans, I mean, so we've had the Antonine pestilence, what then hits the Roman Empire roughly a hundred years later. So it feels like now we're in the heart of this third century crisis period. And what's this next big, I'll say the P word plague event that happens.

Professor Kyle Harper (37:55)

Well in the middle of the third century, first for the Bigger context. The Roman Empire does melt down. And my colleague, the Roman historian Walter Scheidel, has called this the first fall of the Roman Empire. I love that framing because I think it jars us into thinking about this the right way. The Roman Empire falls in the middle of the third century. It's actually weirder that it's put back together. And when it is put back together, it's a really different empire. So from, I would say 268 is like the year of the new empire that lasts down to the early seventh century. It's a second Roman Empire. It has a totally different kind of emperor. So most of the emperors, from Julius Caesar and Augustus to Decius, are sociologically of the same type. They come from wealthy Mediterranean senatorial families who work through the imperial system, where the senatorial elites serve as military commanders as part of their curses, their careers. So they're socially pretty similar. They geographically come from different places, but they're all kind of Mediterranean. Even the Spanish emperors are kind of early Italian Mediterranean emperors and so on. And they represent kind of an urban elite social stratum. From 268. Most of the emperors come from a tiny little region, mostly in what's now Serbia, the bend and the Danube. These are not wealthy Mediterranean senators. These are career soldiers. They're mostly career cavalry officers. People like Claudius, Aurelian, and then ultimately Diocletian and Constantine, who very much come from this social stratum. The Roman Empire is taken over by Serbian cavalry officers who run the show for the whole rest of the way. And there's only real weird exceptions like the Theodosian dynasty, which is sort of the exception that proves the rule. But they change the geography of empire, the social dynamics of empire. Rome ceases to be central at all. People like Diocletian, it's not totally obvious. He goes there before the 20th year of his reign. It's still a culturally symbolic capital, but they say, just screw it. We're going to rule the empire from Trier and Sirmium and eventually Constantinople. And they changed the money system from silver to gold. And eventually they say, we really need some new gods, too. Maybe Sol. Nah, let's go. There's this even cooler God, and we're going to try him out. So they change everything about the empire. It's a totally different empire. So what happens between 251 and 268? These are some of the most transformative years in Roman history. The Roman Empire melts down. It's this comprehensive crisis. There's a financial dimension where the silver Coinage, which had a large fiduciary element. The Roman emperors had gotten away with debasing it without the price scale getting totally out of whack. And eventually they go too far. And for whatever reason the money system really collapses. So there's a financial, economic element to it. There's, there's a geopolitical element. You not only have Goths crossing inside the Roman Empire and they're clearly organized, they're clearly dangerous, they're capable of. And they confront Decius, a Roman emperor, leading the legions into battle and kill him. And that's something new and different. And at the same time, to make matters worse, you have a revanchist Persian regime that's pretty aggressive, that takes power on your eastern frontier. So you now have a totally new level of geopolitical threat. So you have financial breakdown, you have geopolitical change, you have a complete collapse of dynastic legitimacy. This is why we have over 20 emperors in a 20 year period. And all of the trouble that that entails, including ultimately fragmentation of the empire into three empires, the Empire of the Gauls, the empire out of the east, and the sort of core empire in the Mediterranean and Italy. The Roman Empire should have totally come apart. And in that mix there's a pandemic. And it's a pandemic that's been far too neglected. It's not by any means the sole cause of this total meltdown. And in fact the causal arrows go both ways. I think that the pandemic doesn't cause the crisis, but the crisis also aggravates the pandemic. Societies that are unable to respond to problems seem to suffer the biggest consequences of pandemics. And when you can't feed your population, then you're more vulnerable to an explosive pandemic. But there is a pandemic. It's called the Plague of Cyprian, which is named after the Bishop of Carthage. He, you know, I don't know that he would want his name associated with the plague because he didn't cause it. He just happened to write a sermon that happened to get preserved. That happens to be one of our lengthier descriptions of it. And so we call it the Plague of Cyprian. But in fact there's dozens of testimonies to this disease outbreak from what is actually the, like maybe the darkest period of Roman history in terms of its obscurity. To us, we, there are times during these decades where there are people, we're not totally sure if they were emperor or if they're made up that's how bad it is. There's a lot we don't know about this period where we, like, lack basic facts about emperors and battles and the elites. And yet we have dozens of witnesses to this pandemic event. It was clearly, again, something that really stood out. It caused a very nasty, severe disease that they describe is disappointing. We don't know what it was. This is another one. These two have not yet been unlocked by laboratory identification. We're trying. We're trying right now, so we may figure this out. But whatever it was, it was perceived to be a major factor in the troubles that afflicted the Roman Empire. So the plague, or and again, we call it the plague of Cyprium, but it's not really the plague. It's just a pestilence of the 250s that seems to show up about 251. That's been something I've changed my opinion a little bit about because of some work of others that the plague probably shows up around 251. It's a little obscure when it shows up. The only contemporary source we have that comments on its geographic origin says it comes from Ethiopia, which is tricky because the classical Greek historian Thucydides describes the plague of Athens going back the 5th century BC as coming from Ethiopia. And since everybody wants to be Thucydides, if you're a historian, he's like the Michael Jordan of historians. He's like the best of all time. And so everybody imitates him. So we never totally know when somebody says something that Thucydides said, if it's reliable or if it's just imitation. But it's our only claim for the geographic origins. But when it gets to the Roman Empire, it spreads everywhere. Latin sources, Greek sources, Christian sources, pagan sources all describe it as something extraordinary. And it certainly contributes to this phase of crisis that I think we should rightly consider the first fall of the Roman Empire.

Jim (45:52)

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Kyle Harper (47:07)

I love that expression. As you say the first rule of the Roman Empire and how following it, you get a very new look Roman Empire. So far in our chat card we've covered a pandemic from the second century and we just done the plague of Cyprian with the third century. If we now move into the fourth century and this new look Roman Empire, I mean, do we have a similar big pandemic hitting the Roman Empire during that period or is it quite different? Is it a period of recovery? Almost?

Professor Kyle Harper (47:33)

Right. I mean, I think more the latter. We don't have evidence for major pandemics. There's certainly epidemics, there's certainly this sort of not only the normal stew, but the sort of like normal variation in the death rate where there are going to be bad years. We have literary sources that describe years when there's higher levels of mortality from disease. But there's nothing like the plague of Cyprium where all of a sudden in the record you have dozens of testimonies and nothing like the plague of Justinian in the 6th century, which is the granddaddy of them all. And yet the 4th century is the most richly documented period of antiquity. This is something that's sometimes underappreciated. But the fourth century is the most well documented period of the entire ancient world. And there's various reasons for that. The most powerful one is that with the conversion of Constantine to Christianity, you have the rapid spread of the faith and you have the sudden entry into what had been theretofore a minority religion of a highly educated elite. And so this is the social background of the 4th century church, where you have people like Gregory of Nyssa and Basil of Caesarea, Gregory of Nazianzus, you have Ambrose of Milan, who's been a governor, you of Augustine. And so for about a century you have the entry into the church during a really formative phase when orthodoxy is sort of being finalized and there's still a lot to fill in. And you have these incredible people who are sort of there in this century and they become the fathers of The Church. Right. Their writings that fill out Trinitarian Orthodoxy have a huge impact in both the Greek, the Eastern tradition and in the Latin West. And so their writings are abundant and they're preserved. And so we just have masses of material. I mean, I wrote my dissertation long ago on slavery in this period, and there are hundreds of thousands of references to slaves in the 4th century. You can write about the realities of life in the 4th century in a way you can't for any other period. I mean, the, the sermons of John Chrysostom, a priest of Antioch and one time bishop of Constantinople, fill shelves. They're incredibly rich and vivid. So all that's a little bit of a long way of saying, yes, there's recovery in certain ways, and if there had been a plague of Justinian, like pandemic that had wiped out some huge portion of the population, we would be more likely to know about it in the century after Constantine than any other period of the past. We know it in a level of detail that we don't know any other century of antiquity. And there's nothing, there's nothing like the plagues of the 2nd, 3rd or 6th century. There's some big outbreaks. There's clearly an outbreak in the, like, 311, 312 and parts of the Eastern Mediterranean. So, I mean, there's some, like, spikes in the death rate that are probably pretty serious if you're a victim of them. They're nothing to minimize, but nothing really of the scale and certainly nothing of the consequence that sort of has these cascading consequences where it sort of knocks out a pillar of the system and then things start to crash. We just don't have that in the 4th century.

Kyle Harper (51:15)

Almost slightly undermining that idea of some recovery in the 4th century if there isn't one of these great pandemics. But as you get to the end of the fourth century and the beginning of the fifth, of course you get, as already covered in this series, the arrival of these great Romanized barbarian groups that the Goths and the Huns and so on. Is there a sense that maybe behind that movement that the climate, is it changing a bit from the previous centuries? Is it becoming a bit more fickle?

Tristan Hughes (51:43)

Yes.

Kyle Harper (51:43)

Okay. Although there aren't any great pandemics at this time, things like famine and food crises may well affect the movement of peoples like the Huns that influence their movements into the Roman Empire. That will lead ultimately to a lot of turbulence within the boundaries of the empire.

Professor Kyle Harper (52:00)

Right. And this is a very, very active area of research. It's one that I think is interesting and I'm still open minded and I'm kind of excited to see what, what we learn in the next 10 years or so. A lot of this is very difficult. Like I would even separate the Goths and the Huns. The Goths are a difficult people group to study because we're so reliant on archeology, but there's lots of it and it's very good archaeology and, and we know a lot. So I wouldn't understate the challenges, but I would also emphasize that we've, we've learned an incredible amount. Whereas like the Huns are just next level difficult to understand. We don't, we struggle to know who they are. They play a major role in history, although even that has been contested. Whether or not we exaggerate it, whether Ammianus Marcellinus, the contemporary historians going the fourth and fifth century are exaggerating the role of the Huns. So the difficulties are hard to overstate. There's archaeology, but it's more difficult. They're a nomadic group, they're harder to pin down in every way. Archaeologically, they're harder, you know, they're culturally adaptive. So they clearly at times are allied with and integrating their society with Germanic groups beyond the Rhine and Danube. And so it's very difficult to piece together who are the Huns, what's their real role in history, much less than to go a level even deeper, which is to try and understand causally what causes them to show up. Why are they a formidable challenge in the 4th and 5th century? But I think you can certainly start to build a really plausible case that nomadic groups are dependent on the grassland, on the steppe for their herds. They can move great distances very quickly, this is what they do. And they benefit from climate conditions that allow the basis of their wealth, their economic system to multiply and to flourish. And so, you know, I think that we need to try and tease out like what's, what's going on on the step? Are there phases when probably there's population growth because there's economic strength? Are there phases where there's economic challenge because there's say, extreme aridity? And then do these change over time? And there's increasingly pretty good evidence, some of it too. We lean on comparison with the study of Central Asian step groups in the Middle Ages, the late Middle Ages, even early modern times, where we have sometimes better data, where there's pretty strong case to be made that there's a climate link to things like population growth and migration. Patterns. So when we go back to the 4th century, we can at least have that model in the back of our mind to develop ideas and hypotheses. But I think it's certainly possible that one of the drivers of migration in the later 4th century is climate variability. And I do think there's a very strong case to be made that a big part of the story of the Roman Empire is what's going on across the frontier in the trans Danubian world. And that in my view, the sort of new Roman Empire created by Diocletian, Constantine and others, you can certainly make a case that it's sort of doomed to fail. It clearly has its structural weaknesses, but so did the earlier Roman Empire. I think that's kind of a lack of imagination and taking seriously the possibilities or the counterfactuals. The empire also had a lot of strengths and it got really, really unlucky. And somewhere in the interplay of those structural weaknesses and the problems that grew and grew in the form of geopolitical pressure, the Roman Empire cracks in ways that ultimately do divide it and then lead to this thing we call the fall of the Roman Empire.

Kyle Harper (56:25)

I mean, Karl, it's just interesting to theorize, keeping on the Huns a little bit and going back to what you said at the start, how it's not either or plague is the end of the Roman Empire as human things, it's that they go hand in hand and maybe that the movement of the Huns westwards. Could we theorize that potentially they're bringing, maybe some of them are bringing diseases with them, or as they're going into the Western Roman Empire area, they're encountering diseases that they haven't encountered before, like on an epidemic level. It's thinking about that part of the story as well as the human events themselves.

Professor Kyle Harper (56:59)

Yeah, I mean, certainly that's happening at some level. It's just inevitable. When people move, they encounter different environments, they encounter different microbial pools. I will say one of the really surprising things has been the sort of big global history comparison. The Black Death, which is the giant plague at the end of the Middle Ages, is definitely facilitated by things that are going on on the steppe by Mongol takeover. The disruptions that follow that, then the sort of networks of trade and conflict that connect Central Asia to Eastern Europe to the Black Sea. The Black Death comes across the nomadic world. The plagues of late antiquity, so far as we can tell, seem not to, which is interesting. The plague of Justinian in the 6th century, which is the plague, it's Bubonic plague, Yersinia pestis. It does come from Central Asia. We know the evolutionary origins of the plague lie in a pretty specific region. It's right at the intersection of Kazakhstan, Kyrgyzstan and western China, Xinjiang. Somehow this bacterium, you know, it doesn't have legs, it can't walk, something carries it, animals and people, and we're piecing together. But I believe that this plague actually doesn't come across Central Asia, that it actually goes down through South Asia and comes across the oceans. And for whatever reason, it actually seems like the Indian Ocean world is a bigger network for the movement of all kinds of things in the Roman Empire. Ivory, spice, silk, wine, gold, coral, all kinds of interesting things moving around the Indian Ocean. But this includes pathogens. I think we didn't know this until sort of recently, really. That, in fact, the kind of step, as far as we can tell, seems not to be the main conduit. And that in itself is kind of this interesting comparative point that contrasts with the late Middle Ages.

Kyle Harper (59:21)

I'm glad that you highlighted India there, because that is something we haven't mentioned, as you say. But of course, India is the biggest trading partner of the Roman Empire and all of that maritime trade going from the Red Sea to the western coast of India, as you say, pathogens alongside all of these precious goods that are going alongside there. I wish we could talk more about the plague of Justinian. And as you've highlighted, that's the big one and that's the plague in the 6th century. I must ask, though, because this series is largely covering the fall of the Western Roman Empire and the sacks of Rome. So the fifth century, let's say, just before the end of the Western Roman Empire, when you have those last Roman emperors in Ravenna in the late 5th century, has the state of the Empire by that time? It's fractured. Is part of the crisis the fact that it has been also hit by environmental and epidemiological effects, too, alongside barbarian migrations and so on, do they all come together to create a perfect storm that weakens the Western Roman Empire and the Roman Empire in general at that time?

Professor Kyle Harper (60:28)

Yeah, I think so. And we're still debating, for instance, how do we think about the aftermath of 476? It's a huge date. It's not just symbolic. I mean, it is. It's symbolic. I mean, because, you know, we all need. We've all. We've all taught a history survey course, and you've got to give your students a date when the Empire ends to put on the final exam. And 476 is a convenient one, so it's a handy symbol. But it's clearly more than that. There's real underlying political change. But one of the things we sort of still debate is let's think about the 50 years that followed that. Is that a period of recovery? Is that a period of decline, this kind of more or less Ostrogothic phase, between the deposition of the last Roman emperor and the recovery of the Roman Empire by the eastern Rome under Justinian, that takes back the Italian peninsula. And count me among the people who think that there may even be some kind of modest stabilization after 476, that the empire wasn't doomed to fall apart, and that even Justinian's reconquest wasn't a totally doomed effort from the beginning. So I think the 476 is a handy date. It's a real enough moment. And yet the real falls of the Roman Empire I would date to the third century crisis and then to the sixth century crisis.

Kyle Harper (62:15)

Would you date that third century crisis? It's always difficult to pinpoint a single point or at turning points where some could argue that Brems fate was sealed. But does it feel actually that that third century crisis and that midpoint when you have the plague of Cyprian, but also very much the change in the outlook of the emperors, the coinage issues and so on, would you suggest that's a key area to look at?

Professor Kyle Harper (62:38)

Yeah, I mean, I think the third century is a period of crisis and transformation. And what you get in the aftermath of that is something really structurally different. And this structurally different empire then lasts for a really long time. I mean, it in some ways is really as long lasting, if not even slightly longer than the time period between Augustus and Decius. And so we need to think about it on its terms. It's clearly something that is structurally stable enough to prove really, really enduring. And so we have to ask why, I think we shouldn't see that its fate was sealed from the beginning. And we need to be able to imagine alternatives in which if the Huns hadn't invaded, or if the Goths hadn't been such a formidable force, or if there hadn't been a devastating change in the climate and endemic disease, history could have been very different. And the Second Roman Empire lasts a very long time, but it's could have even lasted longer than it did, perhaps.

Kyle Harper (63:51)

And I guess if you take the climate argument as being one of the drivers for the Huns moving west, it begs that what if question, doesn't it? Maybe if the climate and the disease environment had been more favorable, I guess that big what if, like could the Empire in the west or the Roman Empire in the west, could it have endured longer? But I guess that's it's a what if question that could people could debate for ages.

Professor Kyle Harper (64:14)

Well, I hope we do debate it for ages and it keeps historians employed. But the exciting thing to me is that we don't have to just debate it with the same evidence, with the same data sets, with the same texts. We can now read Ammianus Marcellinus, but we can also look at what does tree rings in Central Asia or the Alps tell us about the world in which these people lived. So we can keep debating it, but we should also try and get new clues to piece together the past.

Kyle Harper (64:48)

Carl, this has been such a fantastic chat. Last but certainly not least, your book on this topic, it is called the.

Professor Kyle Harper (64:56)

Fate of Climate, Disease and the End of an Empire 2017, which is already a long time ago in this world. But it certainly touches on many of these themes.

Kyle Harper (65:07)

Kyle, it just goes for me to say thank you so much for taking the time to come on the podcast today.

Professor Kyle Harper (65:11)

Thank you for having me.

Tristan Hughes (65:16)

Well, there you go. That was Professor Kyle Harper joining us for the third episode in our Fall of the Roman Empire series, exploring the devastating role of disease in Rome's collapse. From the Antonine plague to the Justinianic plague. We looked at how outbreaks of deadly pathogens helped bring a mighty empire to its knees.

Kyle Harper (65:35)

I really do hope you enjoyed it.

Tristan Hughes (65:38)

Next up in this series we'll be rounding things off by looking at the final emperors of the West. How did the last men to wear the purple try to hold things together? And why did it all finally fall apart? Thank you for listening to this episode of the Ancients. Please follow the show on Spotify or wherever you get get your podcasts. If you leave us a rating as well, we'd really appreciate that. Don't forget, you can also listen to us and all of Historyhit's podcasts ad free and watch hundreds of TV documentaries when you subscribe@historyhit.com subscribe that's enough from me and I'll see you in the next episode.

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