Pod Insights The Ancients Emperor Diocletian and the Great Persecution About this episode How did a humble Balkan soldier ascend to the heights of Roman power?
Tristan Hughes is joined by Dr. David Gwynn to explore the tumultuous reign of Emperor Diocletian and the significant reforms that pulled the Roman Empire out of its third-century crisis, including the formation of the Tetrarchy to stabilise the empire. However, Diocletian's legacy is heavily marred by his notorious Great Persecution of Christians. Who was the real Diocletian?
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Rome's Crisis of the Third Century
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Emperor Constantine
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Presented by Tristan Hughes. Audio editor is Aidan Lonergan. The producer is Joseph Knight. The senior producer is Anne-Marie Luff.
All music courtesy of Epidemic Sounds
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Transcript Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.
0:00 Tristan Hughes? Ever wondered why the Romans were defeated in the Teutoburg Forest? What secrets lie buried in prehistoric Ireland? Or what made Alexander truly great? With a subscription to History Hit, you can explore our ancient past alongside the world's leading historians and archaeologists. You'll also unlock hundreds of hours of original documentaries with a brand new release every single week, covering everything from the ancient world to World War II. Just visit historyhit.com/subscribe. Hello, I hope you're well and welcome to the ancients as we are getting nearer and nearer Christmas. Now, we've got a very festive topic for you today. Only kidding, we don't. We're talking about a Roman emperor who went far as perhaps as well.
0:44 Tristan Hughes? The most infamous part of his story is that he persecuted Christians. So yeah, he's a bit of a naughty boy in that regards. However, there's much more to his story than just the persecuting of Christians. And the actual persecution itself is very interesting to hear about, like why it was such a failure. That's all to come in today's episode with the one and only Dr David Gwynn. David, he's been on the show several times before. He's a fan favourite as well. He is the interviewee we had for one of our most popular episodes of 2025. That was the origins of the fall of Rome back in May. He's a fantastic speaker, really eloquent and gets the points across so well. And I know you're going to absolutely love it. So without further ado, let's get into the episode.
1:40 Tristan Hughes? He's the emperor who brought one of the most turbulent periods in Roman history to its end. A man who came from humble Balkan beginnings and rose through the ranks of the Roman army to ultimately seize the purple. That man's name was Diocles. We know him better by his official imperial name, Diocletian.
2:03 Tristan Hughes? In today's episode, we're covering Diocletian's story from beginning to end. We'll explore how he transformed the Roman Empire in the late 3rd and early 4th century AD, bringing it out of its 3rd-century crisis. We'll explore the imperial reforms he oversaw, including how he ended up splitting power between four leaders, himself included. We know this rule of four today as the tetrarchy. But we'll also explore the part of Diocletian's story that has greatly tarnished his legacy: the Great Persecution of Christians that happened during the later stages of his reign. This is the story of Emperor Diocletian with our returning guest, Dr David Gwynn.
2:48 Tristan Hughes? He's such a fascinating figure, isn't he, Diocletian? Because he also comes, you know, right at the end of this turbulent period and is, it feels like he's central to the reforming, the transformation of the Roman Empire at that time.
3:01 Speaker 01 Yes, Diocletian is, as you said, unquestionably in the top 10 of great Roman emperors, forever distorted by the fact that our Christian sources despise the man for the Great Persecution. But there is a reason why in modern historical divisions, we talk about the High Roman Empire of the first two centuries AD, the 3rd-century crisis, and then the New Empire or the Later Roman Empire. And there are two great architects of the Later Roman Empire. One is Constantine, the first Christian emperor, but the other is Diocletian.
3:37 Tristan Hughes? He is very much right at the top there, isn't he? And in regards to the sources that we have for him, how many sources, what types of sources do we have?
3:45 Speaker 01 And this is where the problems ultimately lie. Diocletian deserved a brilliant narrative history, someone describing his reign, the triumphs, the setbacks. People did write those histories, we don't have them. There is no coordinated classical narrative historian who covers the period of Diocletian and the tetrarchy. So what we must do instead is piece it together. We've got archaeology, there are only a few monuments, but a few, that survive. And then you've above all got two key categories of evidence. We've got the evidence that comes from Diocletian, his court and his propaganda machine. So that includes laws, but above all includes panegyrics.
4:27 Speaker 01 So speech is given in honour of Diocletian or his fellow rulers. And then on the other side, you've got the Christian polemicists. The Christian writers who lived through the great persecution. And therefore described Diocletian's reign in at times fairly apocalyptic terms, while also aware of the man's importance, most famously Lactentius, North African, and Eusebius of Caesarea, the first great Christian historian.
4:55 Tristan Hughes? And let's set the record straight in regards to the time period that we're talking about with Diocletian. So this is the later third century, beginning of the fourth century with him.
5:03 Speaker 01 Exactly. So Diocletian comes to power in 284 AD. He will voluntarily abdicate, making him almost unique in Roman history in 305.
5:17 Tristan Hughes? Brilliant. Well, now let's talk about his rise to power. So let's get to that stage of 284. First of, do we know much about his origins? Do we know much about his backstory?
5:27 Speaker 01 Not a great deal. The third century was after all, a period of considerable instability. His name is Diocles originally. He's a Balkan peasant farmer who, like many other of those farmers, looking for a chance for a better life, more opportunities, served in the Roman army. Probably born perhaps around 240, but we don't know how old he actually was when he took power. But he's clearly a mature adult because he'd risen through extensive military experience in a period of major turmoil.
6:00 Tristan Hughes? He's got a good time period to do that, to rise through the ranks, doesn't he?
6:03 Speaker 01 Exactly. And he ends up in command of the imperial bodyguard when two emperors in rapid succession seem to die under very unusual circumstances. One of our sources claims they were hit by lightning, both of them. This seems slightly unlikely. Unfortunately, our source for that is perhaps the worst source in all of Rome's history, which is the text known as the Historia Augusta, and basically fake set of imperial biographies that stops just before Diocletian. So he appears, but only as someone near the emperors Charis, Carinus, and Numerian, all of whom die between 282 and 284.
6:47 Tristan Hughes? And of those three, it's Charis and Numerian. They're the two which get struck by lightning, aren't they, in quick succession? Yes, Charis is the dad, Numerian is one of the sons, and Diocles is serving in Numerian's army as one of the highest positions when Numerian falls, oh, sorry, gets struck by lightning. Oh, when Numerian dies, and he's in Turkey at that time, isn't he?
7:09 Speaker 01 Yes. And if Diocles was responsible for imperial safety, you'd have to say he wasn't doing a great job. Although, in fairness, firstly, this kind of event was quite common during the third century, and actually, killed by bodyguards is the single most common form of death for Roman emperors right through their history. It goes back to Caligula. But he was clearly a well-respected soldier, an experienced soldier, and in the right place and well-organised. Because most of these usurpations, that person then gets murdered in turn. During the third century crisis, so above all the period between 235 and 284,
7:50 Speaker 01 the average length of reign was less than three years. There's an incredible turnover of imperial power. Diocletian is going to hold power for 20 years and voluntarily let it go.
8:02 Tristan Hughes? Let's start at the beginning of his reign. So Numerian dies, and his father Charis had died as well, but Carinus, or Carinus, Carinus, however you say his name, he's still around. So do we know how Diocletian goes from being on the spot when Numerian dies to him actually being proclaimed emperor?
8:23 Speaker 01 Not entirely. Unfortunately, we've basically just got a few later, very short summaries, which really just say that Diocles was making some claim for power and then Corinus dies. It doesn't seem to be a full pitched civil war, but in reality, one of the two has to die. This is a standoff that has to be resolved. Diocles is the one who has the army support, has the better structures in place, but exactly how it was all engineered remains very difficult.
8:56 Tristan Hughes? Because isn't there something like the Battle of the Magus River or something like that, that has seen this sometimes that Corinus and Diocletian, they have a big battle and then Diocletian wins it? Or is that less clear whether it actually happened then?
9:07 Speaker 01 It's very unclear whether there is a major pitched battle, whether there's a skirmish, whether indeed Diocles convinces Corinus's army that actually Diocles is the better candidate. This is, it's a problem right through the third century crisis. But the real difficulty when it comes to Diocletian is of course, what we've really got is later sources who know what will happen, trying to give us some kind of reconstruction. And it's interesting that there doesn't seem to have been a single set narrative for them to draw on. So we just get these different accounts, like in the Historia Augusta, probably written a hundred odd years later.
9:44 Tristan Hughes? So what sort of empire? So Diocletian, he's now the man ruling, he's defeated all these potential threats to his rule. What sort of empire does he inherit, has he got at his disposal in 284?
9:57 Speaker 01 In some ways, Diocletian is a bit luckier than talking about the third century crisis might sound. During the worst years of the third century, which is above all the 250s and 260s, the Roman Empire was in severe danger of completely shattering. Different regions broke away, in particular Britain and Gaul break away into their own miniature Gallic Empire. Likewise in Syria, the Palmyrian Empire takes away the eastern territories. It really does look like the empire could be completely collapsing. But in the later 260s and the early 270s, it all got pulled back together, above all by the emperors Gallienus and Aurelian.
10:39 Speaker 01 So the empire has been pulled more or less back into its traditional shape. So it extends from Hadrian's Wall in Britain, down to the Tsara Desert in Africa, out towards the Euphrates River in the east. So Diocletian has actually inherited an empire that was in a little better state than had this been 20 years earlier. That being said, all the frontiers remain uncertain. The Persians are still a major threat to the east as they have been right through the third century. There's turmoil on the Rhine and Danube and obviously if you come to power through what does look like a combination of usurpation, assassination and a few skirmishes, you're going to face rivals.
11:23 Speaker 01 So it's internally very unstable and externally threatened.
11:26 Tristan Hughes? And so what does he decide to do straight away to kind of consolidate his new rule?
11:32 Speaker 01 Diocletian is clearly a pragmatic and highly intelligent ruler. That will come very clear right through his reign. And one thing that has become very obvious across the third century is the Roman Empire is too big for one man to easily control. If everything's stable, then fine, you can have a single emperor as the focus of authority. But if you've got trouble in Britain and on the Rhine and on the Danube and on the Euphrates with Persia, possible revolt in Egypt, one person cannot deal with all that. Diocletian needed to delegate. The problem, of course, is if you delegate authority,
12:16 Speaker 01 you're setting up a potential rival and it so easily leads to civil war. And if there is one thing Diocletian is brilliant at, it is choosing who can he delegate to, who will work with him and create a structure that functions.
12:32 Tristan Hughes? His idea of trying to find, if at all possible, someone who is just unquestionably loyal, no matter what.
12:37 Speaker 01 And the problem, of course, is you need them to be loyal, but at the same time capable of intelligent, independent judgment. And it is a marker of all the most successful leaders in history. That they had the ability to identify the right subordinate. So Augustus, the first Roman emperor, does it with Agrippa, a brilliant soldier who doesn't actually want power for himself. They're not easy to find, but Augustus found one. Diocletian looked back to his own origins. He's not going to look for an ally in the old traditional Roman aristocracy, which he, of course, doesn't come from. He needs a soldier because this is still a military crisis. He needs someone who can work with him
13:22 Speaker 01 and who hopefully will also recognize that Diocletian is the senior partner. He looks back to the Balkans. And interestingly, his basic criteria seem to be he doesn't want relatives. He's not interested in creating some kind of dynastic setup, but he does want Balkan-born soldiers. So the first thing he did was share power. Create, it's sometimes just called the diarchy. It's a sharing of power with one other individual. His name is Maximian. He's another Balkan soldier.
13:56 Tristan Hughes? Maximian, right. And does Maximian, does it feel almost like he will be Diocletian's best buddy, almost Robin to his Batman, can I think?
14:06 Speaker 01 You know, obviously a lot of our sources come from the imperial propaganda machine. And so insist these people are so close, such friends. In reality, they are going to work together remarkably well for the next 20 years. And in a sense, what's the classical pagan equivalent to Batman and Robin? Jupiter and Hercules.
14:27 Tristan Hughes? Love that.
14:27 Speaker 01 And this is actually the symbolism they use. So Diocletian becomes jovial. Maximian is Herculeus. So they're both claiming divine strength, but there's a hierarchy there. Jupiter, the father, the oldest, the king of the gods. Hercules, the great hero.
14:44 Tristan Hughes? And when it is just the two of them, where do they base themselves?
14:48 Speaker 01 So where are you going to prioritize? Well, the greatest single threat is the Persian Sasanian Empire. So Diocletian stays in the east. Increasingly, although he does move around, using the city of Nicomedia, not that far from modern Istanbul, but on the Turkish side in Asia Minor, Maximian gets sent westward. Because the most immediate single concern is the person that Diocletian had hoped would help stabilise the Rhine and in particular Britain, has decided to set up his own miniature empire instead, this is Carausius. And so Carausius has seized power in Britain. Maximian's job is going to be to stabilise those regions. So where does Maximian go?
15:31 Speaker 01 He goes to Trier, on the modern French-German border.
15:34 Tristan Hughes? So they're quite far apart. I mean, but how effective does this diarchy prove? Or does Diocletian, well, we already know the answer to this of what will ultimately happen, how long before he decides, actually, I need to divide it even further?
15:46 Speaker 01 Dividing power between two rulers had been quite common in Roman history. Marcus Aurelius had done it back in the second century. It happened quite often in the third century crisis. So there's a well-established precedent for this. And Diocletian probably did hope that that was what would be sufficient.
16:03 Tristan Hughes? Oh, father and son as well with Valerian and Gallienus. We've covered that previously, haven't we?
16:06 Speaker 01 Exactly. So, you know, so this idea of just sharing power, having two people with the title Augustus, that's not going to surprise anybody. And that's probably where Diocletian was originally planning to leave the situation. The problem is firstly, Diocletian himself discovers that firstly, there are major internal problems with the government, with the economy, that need close attention. But there's also the Persian threat and the need to stabilise the Danube, and he can't do all of those things from the east. Maximian, because he has to keep half an eye on the Rhine River, fails to defeat Carausius. Carausius would actually end up being murdered by his own subordinate Electus, who then carries on with the revolt.
16:51 Speaker 01 But Maximian fails in that aim. Basically, Diocletian pragmatically again tried to just have a shared power between two rulers, which then remains in place for a decade, very nearly.
17:08 Speaker 01 But then he came to the radical decision that two is not enough. That actually there are so many pressures, so much needing changing. That he's going to do something that has never been done before. And that is create a tetrarchy.
17:24 Tristan Hughes? A rule of four, that's the thing, isn't it? So who, if he decides he now needs to find two more. I mean, finding, you know, that person who's clever but loyal, finding one of those as a Balkan soldier, another Balkan soldier. Initially, it sounds like it was, is quite a challenging task. He's now got to find two more of those. So how does he go about doing that?
17:44 Speaker 01 And remarkably, he's going to get this one right as well. He once again just looks to the Balkans. So again, people not from the high aristocracy, but soldiers of proven ability, proven intelligence. Who Diocletian clearly believes can work within the system. And he finds two more. Flavius Constantius, Constantius Chlorus, as he's often known, the father of Constantine. But that's not why he was chosen. He's another successful soldier. And Gylareus, the fourth member of the tetrarchy who's going to work with Diocletian. Because the idea of the tetrarchy is not four equals.
18:24 Speaker 01 Sharing power with one other person who has the same high title of Augustus, that was traditional. To have four Augusti, there would not be a precedent for that. It would also be very unstable. So the tetrarchy is not four equal people. Instead, these next two, Constantius and Gylareus, are given the title Caesar. As so often, the titles, of course, go back to Julius Caesar and Augustus. But the Augustus is the senior, the Caesar is the junior. Constantius goes westward. So Constantius will be the Caesar to Maximian as the Augustus. Gylareus stays in the east, he's Diocletian Caesar.
19:05 Tristan Hughes? And he's in Thessalonica, is that that area, northern Greece?
19:08 Speaker 01 And then it's a case of where do you send them?
19:10 Tristan Hughes? Right.
19:11 Speaker 01 So step one, Maximian, interestingly, pulls back towards northern Italy. From which he can watch the Rhine and the upper levels of the Danube. Constantius's job is Britain. Sort out this revolt of Claudius and Electus, he's going to do that. Gylareus and Diocletian, interestingly, don't follow such a clear cut geographic pattern.
19:32 Speaker 01 Diocletian's chief residence is Nicomedia in modern Turkey. Galerius has indeed left us, the very, it's only a few remains of a great arch in Thessalonica in Greece. But it's also Galerius who gets the job of fighting the Persians. So Galerius and Diocletian, it's much more a who's looking after what sphere rather than who's going to be in which region. Diocletian is going to focus on the government, the economy, getting the internal structures working. Galerius gets the job of facing the Sasanian Persians.
20:04 Tristan Hughes? I was about to ask, going on to military activity, do we hear much of Diocletian's personal military activity once he becomes, once he becomes an emperor, once he becomes one of the Augusti? It sounds like then we don't really.
20:17 Speaker 01 No, he's clearly a highly capable soldier, or he'd never have risen through the ranks in the first place. But like so many actually very good soldiers, his great strengths lie in logistics, in organisation. He's clearly a perfectly competent military commander, but the only struggles we see him directly involved in tend to be subduing revolts like in Egypt. It's not in trying to win major battles. The same is true of Maximian, whose most famous major campaign was the attempt to win in Britain that fails. It does look like that one of Diocletian's criteria for the Caesars was these were going to be the men who were going to be active on the battlefield. So Constantius is clearly very effective and very efficient in suppressing the British
21:02 Speaker 01 revolt. It's Galerius who's going to achieve the greatest single military success of the Tetrarchy, because the Sasanian Persians who emerged in the 220s have been fighting the Romans basically ever since. And the Romans have never won a major conflict until in 298, that's exactly what Galerius does.
21:22 Tristan Hughes? Well, let's focus in on Diocletian, and I think this is where it gets really, really interesting, his policies and his portrayal. And if you focus on his portrayal first of all, once he's now divided power between the two Augusti, including himself and these two Caesars, and they're doing their own stuff in different parts of the empire, how does Diocletian go about portraying himself? Because you mentioned right near the start that he has a propaganda machine at his disposal.
21:48 Speaker 01 And after all, what's going to be almost everyone's assumption when you have a Tetrarchy? There's a civil war coming. Sharing power has a long established tradition, not just in the Roman world, for this will lead to conflict, to tension.
22:01 Tristan Hughes? Where's the concord exactly?
22:03 Speaker 01 Precisely. So how are you going to express the harmony? How are you going to build the ideology? And that's what the propaganda machine is working towards. So we have a number of panegyrics addressed to particularly actually Maximian, because they survived in Latin, but always addressing Maximian as part of a duo. This idea of Jovius and Herculeus and the two Caesars take the same title as their senior. So Constantius gets linked to Hercules, Galerius gets links to Jupiter. So it's binding them together. But probably the single most famous example of the Tetrarchid ideology you can still see today if you go to St Mark's Square in Venice.
22:45 Speaker 01 It's fairly self evident that's not where it was originally based, not least because Venice didn't matter in this period. But built into the wall of the church is the famous porphyry group of all four tetraples.
22:59 Tristan Hughes? It's that purple material, isn't it? It's very striking material, but also one of the most recognizable pieces of sculpture from this time period.
23:06 Speaker 01 Exactly. Porphyry is a purple tinned stone. Purple's the imperial colour. So porphyry is only used for imperial monuments, including sarcophagi. But in this case, this is the finest single piece of porphyry sculpture. So the stone's from Egypt. It was set up originally in the east, probably in Nicomedia. It was taken from Nicomedia, where it was under the Tetrarchid, to Constantinople. At some point after Constantinople's foundation, it can't have begun in Constantinople because that city had not been refounded in the Tetrarchid's time. But that is where the Crusaders in 1204 found it and took it westward. We're as certain of that as we can be, not least because there's a foot missing
23:50 Speaker 01 from the statue that's in Venice and the foot turned up when they were building the Istanbul Underground.
23:56 Tristan Hughes? No way.
23:56 Speaker 01 So we're pretty sure about the origins of this statue.
24:00 Tristan Hughes? They found the actual foot and they've verified it.
24:03 Speaker 01 They believe so. It certainly would fit with the rest of the statue group. But of course, what's the real significance of this? This is a group of four statues. They're in two pairs, each embracing the other. They're dressed identically in military equipment. These are soldier emperors. But the four figures aren't actually totally identical because two of them have stubble. Now, that's a Roman iconographic motif for seniority.
24:35 Tristan Hughes? Seniority, isn't it?
24:36 Speaker 01 And it does, basically, the two who have their arms round the outside of the others are the two seniors. So there is that slight distinction, but otherwise, these people are identical.
24:48 Tristan Hughes? It is such a striking statue, and I'm really glad we covered that. I mean, with Diocletian himself, so he's with the propaganda machine. It's this idea of concord and harmony with his fellow rulers. With Diocletian, of course, he's got very humble, modest origins, doesn't he? So is there attempts with with things like coinage and so on to portray himself as more, as having more legitimacy as ruler? Do we get more of that?
25:13 Speaker 01 It's a challenging topic with Diocletian. Most of what we've got in the material culture is using traditional imagery. So the coins we have draw on a traditional set of images. They don't add massive new titles. They are using traditional language. So after Galerius wins against the Persia, the Persians, all the Tetrarchs can take the title Victory Over Persia. Likewise, when Constantius settles Britain, they all, even Diocletian, never came near Britain, take that title. In some of our later sources, particularly the ones written around the 360s, so two generations later, you get an emphasis that Diocletian particularly loved imperial splendor,
25:57 Speaker 01 that he particularly wanted an ornate diadem, the right gems, purple robes, that he gave himself titles like Dominus. It's not actually clear from the contemporary evidence that there's a particular emphasis. There's certainly a stress on we are the true legitimate emperors. We have divine support and religion is a key part of this ideology. But is it dramatically more marked than, say, Aurelian in the third century crisis? Actually, Aurelian portrayed himself in almost exactly the same language and with the same religious emphasis that there is a divine support. Like so many things Diocletian does, almost none of it is radical revolutionary.
26:42 Speaker 01 The tetrarchy itself as a structure perhaps comes closest. What he's doing is taking things that already existed, but giving them new uses, new interpretations.
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28:07 Tristan Hughes? If we now focus on various administrative achievements of Diocletian, what are, during his rule, if you're also saying that he doesn't really take part in the military sphere during this period, what are some of the bigger administrative achievements that he oversees during his reign?
28:23 Speaker 01 After all, the problem with taking military affairs in isolation is always an army only functions because its supply lines work, the tax revenue is paying for them, equipment's being produced. The structure has to be in place. The actual successes of the tetrarchic armies, perhaps more than anything else, demonstrate how well the administration has managed to stabilise, always with limits, but overall, the Diocletianic model functions. And once again, he's looked at what happened during the third century, at some changes that are unavoidable, but also at parts that must work better, both to support the army, but also of course to prevent local unrest and prevent a usurper rising up against him.
29:08 Speaker 01 So the single most famous of Diocletian's reforms and one that will work extremely well, and indeed for centuries to come, was he looked at the map of the Roman provinces. So right across the empire, all the regions are divided up into provincial blocks and each province has a governor. And quite basically, Diocletian doubled the number of provinces, without taking a single territory. He, in other words, splits almost all of them in half. So he makes the provincial structure more complex and much smaller.
29:43 Speaker 01 At the same time, he also makes it very clear, something that Constantine will then continue, that you've got provincial governors and you've got local army commanders and they're different people.
29:53 Tristan Hughes? He likes divisions, doesn't he? He really sees divisions as the way forward.
29:57 Speaker 01 Exactly. So separate out civilian and military affairs. Again, it had been happening in the third century, but very erratically. Why is he doing this? Step one, smaller provinces are easier to control. So a local official is going to be unable to develop a major power base. It's also therefore easier for a local official to administer. Smaller groups are easier to control. You do of course sometimes need to then deal with provinces as a group. So another layer gets added. Interestingly, given that the terminology will all be taken over by the Christian church, these are the dioceses. And the Roman diocese under Diocletian is a block of provinces
30:40 Speaker 01 with one official over all the provincial governors, whose title is vicarious.
30:46 Tristan Hughes? Is the origins of the word diocese from Diocletian? Or is that that too much of a stretch?
30:50 Speaker 01 It's not from the name Diocletian, but it's from this provincial division. Just as the person in command of a diocese is a vicar. The title's actually vicarious. Because you need that layer now. If you've got so many provinces, there'll be some issues that it shouldn't go to the emperor. They should just go to one person who's dealing with four or five provinces. So it's going to have more of a bureaucracy, which obviously means more officials to pay.
31:18 Speaker 01 But on the other hand, it will be more efficient at a local level, easier to control, but also actually better for tax revenue.
31:25 Tristan Hughes? Is this also contradicting, though, one of those old supposed ideas of the Roman emperors of before him, that a Roman emperor should be available for anyone? You know, I mean, obviously, realistically, that's not going to happen. But this idea that actually a Roman emperor could be addressed by an everyday person if he was passing through kind of thing. Is that almost a transformation in that by, even though I said realistically, that was never going to happen anyway, but is Diocletian making it almost official now, saying that if you've got a problem, you don't always have to raise it with me. There are these people who I've given enough power to, to sort it for you instead of me?
32:01 Speaker 01 The old Roman model, which emerges with Augustus the First Emperor, and then in the first two centuries AD, is indeed that people should be able to send petitions through to the emperor. So Pliny the Younger famously does under the Emperor Trajan, including Pliny's letter, saying, I've met Christians, what do I do now? Hadrian, who travelled the entire empire, received petitions wherever he went. And when things are stable, that model could still potentially work. The problem is, of course, the third century crisis has destroyed that stability. And yes, you now have a more organised process. It doesn't actually stop petitions reaching the emperor, but they're going to have to go through multiple
32:43 Speaker 01 stages. So one of our greatest legal collections for the later Roman Empire is the Theodosian Code, named after Theodosius the Second, because it was compiled in the early fifth century. But it contains laws from 306 onwards. So unfortunately, not much help with Diocletian, but does cover Constantine. At least some of those laws are quite clearly responses to somebody raised a question with a provincial governor, who passed it to the vicar, who passed it to the Praetorian prefect, the highest level of the administration, who took it to the emperor. The emperor replied to the Praetorian prefect, and that's the law that's in the Theodosian Code. But some of them, like a tax break for someone with 14 children.
33:27 Speaker 01 That can't have been a matter of imperial policy. So the petition system is still functional, but yes, it is much more restricted. In that sense, it's more autocratic. One of the difficulties here, the original model for the Roman emperors, the one that emerged under Augustus, way back at the turn of B C A D, was the idea of the princeps. So the Roman emperor as the first among equals. That is an ideology was already largely dead by the end of the second century. It was buried in the third century crisis. These people are military emperors, almost all the third century emperors are. So they're not so worried about that old imagery. But they do actually still want to be able to receive those petitions, if only because
34:12 Speaker 01 that's how you know if things are going wrong.
34:15 Tristan Hughes? So it's a nice way, a nice communication, as you say, to get a sense of what's, what's it like on the ground outside the palace and so on. One last thing on those reforms, with those administrative reforms into tax and to the division of these provinces, you mentioned how like the army is still able to function. I mean, was there, although Diocletian himself wasn't at the forefront of the army as they were doing their, their campaigns, do you see military reforms in this period and are they, is that part of Diocletian's legacy?
34:42 Speaker 01 Yes, because Diocletian once again took a look at the third century. What were the lessons learnt during that 50 years before he took power? That included the fact that you needed smaller army units that were more flexible, could more easily respond to crises, and you need cavalry. The Romans had never been as strong on cavalry as they had been on infantry, but in the third century, the need for a good cavalry arm became more and more apparent. And the third century emperors who tried to resolve the crisis like Gallienus and Aurelian, this is what they were developing. Diocletian took a look at those developments and set about trying to work out a more systematic
35:24 Speaker 01 pattern. So you get a marked increase in the number of legions, but it doesn't actually mean there's a massive increase in the army, because the size of a legion seems to have been significantly reduced. So whereas the classic Roman legion, the one you see in reenactments, the one that goes back to the late Roman Republic, 5,500 men in a legion, becomes more like 1,000. And that's on the evidence of the army camps that Diocletian and the other Tetrarchs build along all the major frontiers. Diocletian's looking at the infrastructure, the roads, the camps. So we get told by one particularly hostile
36:05 Speaker 01 source, that's the Christian Lactantis, that every Tetrarch wanted a larger army than any emperor had had before, so the army must have therefore increased four times. There's no earthly way the Roman army increased four times from its old rough estimate of, say, 300,000, because there's no way the Roman Empire can support a million men in the army. The modern estimate, I think, would be that there is an increase in the number of soldiers, just not anything like as drastic as Lactantis is claiming, but perhaps up from 300 to 350,000 to perhaps 400,000. And in the context of ancient medieval history, that is a phenomenal
36:49 Speaker 01 military to have as a standing professional army. You only have to compare it to, say, the kingdoms of a thousand years later, to realise this is a different scale.
36:57 Tristan Hughes? Absolutely is a different scale. And I didn't realise, actually, that the army increased at the time of Diocletian, as well as that kind of difference in the composition. I feel we need to move on now, though, to that. I think it's, let's say, sometimes overarching, infamous part of Diocletian's story, which of course is his approach to Christianity. Now, can you set the scene for us here, David? Christianity, let's say in 284, at the beginning of Diocletian's reign, how big, how big is it in the Roman Empire?
37:29 Speaker 01 Nothing overshadows Diocletian's reputation like the Great Persecution. It's why he misses out on so many of the canons of great emperors. And yet, there's two key things here. One is, the Great Persecution makes sense within Diocletian's overall vision. In other words, it can't just be separated off. It's not some odd aberration and yes, everything else he does is sensible. For Diocletian, it all made sense. The second is indeed, it's a direct response to what's already been happening. So Christianity, of course, originating back in the time of Augustus, back with the birth of Christ, Christianity's been growing across the 280
38:09 Speaker 01 years since, faster than any other religious movement the Romans or Greeks had ever met. But nonetheless, by Diocletian's accession in 284, there were perhaps 6 million Christians? That's in an empire of 60 million.
38:26 Tristan Hughes? So 10%, roughly?
38:27 Speaker 01 Exactly. So roughly 10%. We've got no accurate figures. But the fact that we've got no big churches that have been found, we can roughly reconstruct where there were bishops, where the church hierarchy was beginning to emerge. That's what the rough numbers suggest. So it's the single biggest religious minority bloc in the empire, but it is a very distinct minority. But most importantly, up until the beginning of the third century crisis, the Christians had never been systematically attacked by emperors. They were always regarded as suspect. They could be attacked if there was a particular reason, such as Nero needing
39:07 Speaker 01 someone to blame for when Rome burnt down. But the overall imperial policy in the first two centuries AD is the one laid down to Pliny the Younger by Trajan, which is that Christians are illegal. If you ask someone if they're Christian and they repeatedly say, yes, they die, but don't go looking. As Trajan famously told, we're not hunting them down and we're not interested in anonymous claims that, oh, my neighbour's Christian. But if a Christian is brought forward, you can be killed for just being a Christian, not for any other reason. So they are certainly suspect, but they haven't been systematically attacked.
39:49 Speaker 01 That changed in the middle of the years of the third century crisis. Above all, because one of the basic religious principles of the ancient world is when things are going wrong, the gods, the goddesses must be angry. What's brought down divine wrath? It's a concept sometimes best summarised as the Pax Deorum, the peace of the gods. If you break the Pax Deorum, the gods punish you. Well, around the year 250, the Roman Emperor Desius, who was facing major problems in every direction, decided he had to address this problem of divine anger. We don't actually think he meant to persecute Christians.
40:34 Speaker 01 What he did was pass an edict ordering everyone to sacrifice to the gods across the empire. It turned into the first great empire-wide attack on Christians, when the Christians refused to do it, because of course Christians won't sacrifice to the ancient gods and goddesses. So you have a short-lived persecution by Desius around 250, which was ended because Desius was killed by the Goths in 251. Valerian then attempts a deliberate persecution of Christians in the later 250s, systematically attacking the churches they could find, the bishops, but Valerian is then captured by the Persians and eventually turned into a Persian monument.
41:18 Speaker 01 And as a result, that persecution ended. So there have been imperial attacks on Christianity in the 250s, but they didn't end well for the emperors involved. For the next 20 years, it seems to have been relative peace. Basically, the emperors have other things to worry about, and it doesn't look like persecuting Christians works very well. So by the time you get to 284, Christians are a growing minority within the population. They've expanded, not least because Christianity offers charity, offers welfare. So in a time of crisis, the Christians show their strength. But they are also regarded as a potential threat to stability, above all, a potential threat to the will of the gods.
42:02 Speaker 01 And Diocletian and all the Tetrarchs are devout believers in the old gods.
42:08 Tristan Hughes? And so when does Diocletian go from having misgivings about the Christians and his fellow Tetrarchs to ultimately deciding, right, we're going to do a great persecution of the Christians?
42:20 Speaker 01 It is very noticeable that taking action on religious grounds is the last of Diocletian's major stages. He wanted the army organised, he wanted the provincial structure revised. He worried about the taxation system, about the economy. Only when all those pieces were in place, does he seem to decide now he can focus on religion. So there is no indication of major attacks on Christians or other religious groups in the first 15 years. So when he's co-ruling with Maximian or in the early years of the Tetrarchy, the change seems to come around the year 300.
43:01 Speaker 01 Interestingly, the first religious group he seems to have targeted wasn't actually the Christians. It's a group called the Manicheans. Now, Manicheism is a very unusual hybrid religion, really, between Persian, Buddhist, Christian, Jewish elements. It began in the Persian Empire in the third century. But while Mani, the founder of Manicheism, claimed to be a disciple of Jesus Christ, his basic religious view is dualist rather than monotheist, which is in tune with the Persians who are Zarostan dualists. So it's a principle that there is light and darkness, and they are eternally in conflict.
43:42 Speaker 01 And Manicheism drew on Judeo-Christian ideas, Zarostan ideas, and Buddhist ideas entering the Persian Empire through India to create a new potential global religion.
43:55 Speaker 01 And Manicheism then spread out. It's actually unique. It is the only religion ever persecuted by pagan Roman emperors, Christian Roman emperors, Persian shahs, Islamic caliphs and Chinese emperors. No other religion ever achieved what I refer to as the grand slam of persecution. And actually, the Manichees will survive until after AD 1000, when unfortunately their last communities were on Genghis Khan's line of march. We don't think Genghis Khan had anything specifically against them religiously. They just were in the way. So Manicheism is a fascinating religion in its own right. But it makes it interesting that that seems to have been the first target.
44:39 Speaker 01 Because we have an edict passed by Diocletian, we think in the year 302, that outlaws Manicheism. And the reason it's a very important edict, we don't have Diocletian's edicts against Christians. None of them survived. So our closest indication of how Diocletian would have argued is in the edict against the Manichees, which is that people should be following the old traditional gods, not angering them with new customs. All of that could have been said about Christians. The only thing that's specifically about the Manicheans is they're also Persian. And that makes them even less acceptable. But it's only therefore around 30302
45:24 Speaker 01 that we get this law against Manichees and we get the first stirrings of what's going to become the Great Persecution. And do we know what happens during the Great Persecution? This is where we do get lucky. Because two eyewitnesses who survived the Great Persecution lived to write about it and write about it within the next 20 years. So we have Lactantis, the North African Christian, who was actually teaching Latin rhetoric in Nicomedia, Diocletian's residence, when the Great Persecution began, and describes its very first edict going up and someone tearing it down and being burnt as the first martyr of the persecution. And we have Eusebius of Caesaria, the church historian.
46:07 Speaker 01 Caesaria is in Palestine. Eusebius travelled around Syria, Palestine and Egypt and recorded the violence that was done. So we can actually reconstruct a significant portion of the Great Persecution. What we don't have is its motives. Because we don't have any of the edicts? Interestingly, Lactantis and Eusebius, we think independently blamed the same person, which isn't Diocletian, it's Galerius. It's Galerius of the original Tetrarchs who's held as the most responsible.
46:42 Tristan Hughes? But yet, Diocletian is the one who gets the blame pinned on him in later history, right? I wouldn't think of Maximian with the Great Persecution.
46:49 Speaker 01 No, it's remembered as the Diocletianic persecution. He is the senior Augustus. It's sometimes been hypothesized that Galerius forced Diocletian into it, but firstly, Diocletian doesn't seem to be forced into doing anything else. But more importantly, ideologically, it does fit. If you're trying to present yourselves as delivering a recovery, a key part of that in a world where everybody believes in divine providence is the religious element. You can see exactly the same thing with Augustus, the first emperor. A key part of how he presents his power is pleasing the gods, showing the religious harmony. That's what the Tetrarchs are trying to do.
47:34 Speaker 01 Where there's a real difference is because there are four Tetrarchs, there's no guarantee they all actually thought the same. Constantius Clorus, so the Caesar in the West, is claimed in our sources to have done basically nothing. Now, he's Constantine's father, and they all wrote under Constantine after Constantine's conversion, so we'll always be slightly suspect. On the other hand, Constantius is in Britain, and that's one of the least Christian areas. I mean, to say Christians are 10% of the population does not, of course, mean they're 10% everywhere. In some places, it's more; in Britain, it's quite definitely less. So Constantius probably didn't see much need to act.
48:16 Speaker 01 Maximian in the West, far as we can tell, the Great Persecution hit hardest on the city of Rome itself and North Africa, where it will trigger a major schism known as the Donatus Schism. Whereas we've got much more detailed evidence for what happened in Syria and Egypt, but that's because that's where Eusebius is. But it does look like the Tetrarchs differ slightly, at least in execution. None of them seem to object to it on a matter of principle.
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49:56 Tristan Hughes? Presumably then, I'm guessing that this persecution isn't very successful. I mean, what do we know about the outcome of it? First of all, do we know any extent of the amount of Christians who lose their lives in it, and how long it lasts, and what is ultimately the outcome?
50:10 Speaker 01 And trying to weigh up the Great Persecution's implications has always been a challenge. After all, Eusebius is specifically trying to describe the terrors that were inflicted, and therefore probably does exaggerate the actual level of physical harm. The Great Persecution wasn't aiming to kill Christians. Its first aim is to actually get them to stop being Christian, get them to reintegrate. They tried to pass edicts like "we will imprison people who won't sacrifice," but imprisonment isn't a Roman punishment, not long term. Running a jail takes resources, you don't want to do that. So there's no question, there was genuine violence, people did suffer. But the greatest impact of the Great Persecution on the Christians is psychological as much
50:55 Speaker 01 as it is physical. Because people like Eusebius of Caesarea, who was born in 260, had got to the age of 40 without ever experiencing persecution.
51:06 Speaker 01 So it's a major shock to the Christians who've grown up since Valerian's time, who've never met this kind of imperial hostility. So you do see that in both Lactentius and Eusebius, just the psychology of its impact. But the reason, more than anything else, that it failed, two reasons. One, the strength of the church. Six million people is too many. This is whatever Diocletian would like to achieve, not a totalitarian state, because it just doesn't have the resources to be one. This isn't a 20th century situation like Nazi Germany. So to try and carry out this kind of scale of persecution, logistically was very difficult.
51:48 Speaker 01 But more important than that, the vast majority of the population of the Roman Empire did not want it to happen. And this is the key difference to how Christians were treated back in, say, Nero's time in the first century AD, when they were odd, they were suspect. Stories were going around that Christians practiced cannibalism or incest. Those kind of stories aren't circulating in 300. Instead, everyone's seen the third century crisis. The Christians are simply part of society, they don't cause any real problems, and they're kind of useful. And so what seems to be the local pattern pretty much everywhere in the empire is that
52:28 Speaker 01 the edicts go up, but the local governors don't want to do it, the army doesn't want to get particularly involved, the local population don't care. And if you don't have that local upsurge, the persecution cannot be effective.
52:44 Tristan Hughes? So it kind of peters out, do we think? And I guess, is it helped by the fact that Diocletian, I mean, he doesn't, he's not ruling for much longer, is he? So what is the end of Diocletian's rule? What's the story?
52:54 Speaker 01 So it goes in several stages, the Great Persecution, to answer that question in a sense first. So technically, the Great Persecution ends in 313. So it will have continued for a decade, but actually, it's been very much Fitzstarts. Galarius himself decides in 311, just before he dies, that he will pass an edict saying, "No, the persecution ends." I've always rather liked it as an edict because Galerius is not sorry. This isn't a we shouldn't have done this. This is we did this for the best reasons because this is what would have been best for the empire, would have been best for the gods, but people have carried on being Christian, so we're stopping. It's very much, you, okay. We tried. We've, yeah, precisely.
53:39 Speaker 01 It's actually the only surviving statement by any of the original tetrarchs on the persecution. Whereas Diocletian starts it in three oh three, but abdicates in three oh five. He abdicates as an emperor. And voluntarily stands down, as does Maximian, although we get the distinct impression Maximian didn't want to, and Diocletian didn't give him the choice. What we just don't know is whether this was built into the original tetrarchic agreement. After all, the basic problem with the tetrarchy is what happens if, say, the juniors decide they don't want to be juniors anymore? How do you control the ambition, prevent a civil war? What seems to have been agreed, we just don't know exactly when,
54:23 Speaker 01 is that at a certain point, the two seniors will stand down, the two juniors will become seniors, two new juniors will be appointed. And it just repeats, that's the idea. And so the cycle could repeat. It ends up being effectively Diocletian reaches 20 years in power and then begins the abdication process. Whether it was agreed when the tetrarchy came into shape in two nine three, we don't know that. But certainly that's what happened in three oh five. Diocletian and Maximian stand down. Maximian will launch an attempted coup to come back. That's why we're pretty sure he didn't want to and will end up being killed in the next couple of years. But it says a lot about Diocletian, we don't know when he died.
55:09 Speaker 01 Basically, he abdicates. He had a palace built for himself at Split.
55:14 Tristan Hughes? Oh, this is Diocletian's palace, yes.
55:16 Speaker 01 Sadly, heavily damaged in the Balkan conflicts of the last thirty years. But a magnificent palace, that's where he went. And best guess, because that's all it is, he died in 311 or 312. So he's actually lived for five or six years, completely untroubled by absolutely everybody, except that apparently Galerius occasionally dropped by for some advice, now that Galerius was the new senior.
55:42 Tristan Hughes? Visiting the old emperor, giving some advice. It's such a unique situation as well, isn't it? I would think of, also, you've got, well, Cincinnatus, isn't it, the case of a Roman giving up power? Sulla going into retirement as well, and now Diocletian with his lovely palace in Split. It's also one where, if it was that system of twenty years, if Diocletian, he doesn't last long, I guess he doesn't live long enough to see it completely collapse, which maybe, I guess it's hypothesis, whether with the rise of Maxentius and Constantine and the likes, thinking that this system was put in place, but it will, it will not, it will not endure after him, really.
56:26 Speaker 01 No, and whether actually on some sneaking level, he possibly even took pride in that, in that the tetrarchic system is utterly flawed by almost any measure of human nature and likelihood of civil wars. It hasn't worked for the previous decade because it's a great system. It's worked because the man who built it controlled it. And as long as Diocletian was in power, the tetrarchy does actually work remarkably well. It delivered ten years of stability as a tetrarchy, another ten years before that with Diocletian and Maximian. It's a phenomenal achievement. But as a structure, the tetrarchy only works when there is actually someone who's controlling it properly.
57:09 Speaker 01 What really did the damage was that firstly, the tetrarchy is not dynastic at all.
57:17 Speaker 01 So when they had to appoint two new juniors, they bypassed the children of the existing tetrarchs, in particular Maxentius, the son of Maximian, and Constantine, the son of Constantius Clorus. That's going to leave those two inevitably somewhat unhappy. My father held this high power, why can't I? It seems to mean a conscious choice, but it ignores that threat. But what actually simply destroyed it is the fact that one of the two new seniors, Constantius Clorus, dies a year later. And that immediately puts pressure on Galaris, who's the only surviving senior. And it broke the system because rather
57:58 Speaker 01 than wait for a new senior to be arrived, which should be the new junior being promoted, and a new junior being promoted in turn in the West, Constantius's army hail Constantine.
58:08 Tristan Hughes? And that's the story for another day, the ultimate, the rise of Constantine and the, yes, the complete, well, not removal, but as I say, the evaporation, the disintegration of the tetrarchy. But still, it feels like although Diocletian's legacy is overshadowed by the great persecution, as we've highlighted there, there is so much more to his story that is to be lauded and really focused on with the tetrarchy and everything else. David, this has been a wonderful conversation, and it just goes for me to say once again, thank you so much for taking the time to come back on the podcast today.
58:43 Speaker 01 My great pleasure.
58:52 Tristan Hughes? Well, there you go. There was fan favourite of the podcast, Dr David Gwynne, returning to talk through the amazing story of Emperor Diocletian. He's such a remarkable figure. It was really interesting to sort fact from fiction regarding his great persecution of Christians and how he remodelled the Roman world in the late third and early fourth centuries AD. I hope you enjoyed this episode just as much as I did recording it with David. Thank you for listening. Lastly, accord your little mention that if you enjoyed this episode and you're new to the show, well make sure to follow The Ancients on Spotify or wherever you get your podcasts, so you don't miss out when we release a new episode twice every week.
59:34 Tristan Hughes? If you enjoyed the episode and you'd be kind enough to leave us a rating, well we'd really appreciate that too. Don't forget, you can also sign up to History Hit for hundreds of hours of original documentaries with a new release every week. Sign up at historyhit.com/subscribe. That's all from me, I'll see you in the next episode.
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