The Empire Strikes Back: Diocletian and the Dominate (284–312)

[Diocletian] was a very industrious and capable Emperor, and the one who was the first to introduce in the Roman Empire a practice more in keeping with royal usage than with Roman liberty, since he gave orders that he should be revered with prostration, although before him all (Emperors) were simply greeted. He had his clothing and shoes decorated with gems, whereas previously the Emperor’s insignia comprised only the purple robe.

Eutropius Breviarium 9.261

Diocletian and Maximianus

As it emerged from its age of anarchy, Rome’s ‘broken society’ craved a strong, energetic government that could deliver stability, confidence, and law and order, mend the material and financial damage of the last fifty years, and fight corruption. In Diocletian it now had the hard case it needed, a ‘man with a plan’ who would grab it by the balls and drag it into a new era. Diocletian seldom minced his words, and some scholars have felt that his head-on approach to problem-solving came at the price of totalitarianism:

In this view the Empire was oppressive, drab, uniform and regimented, governed by puritanical autocrats and self-seeking officials. Its resemblance to Stalin’s USSR or Hitler’s Third Reich was not surprising.2

One reason for this viewpoint is that Diocletian seems to have finalized the Roman Empire’s transformation from the Principate (Princeps = ‘First Among Equals’) to the Dominate (Dominus = ‘Lord and Master’).3 The Roman Emperor started to resemble the Hellenistic kings who succeeded Alexander the Great or the Great Kings of Persia rather than Augustus, demanding prostration and working a gorgeous, bejewelled Oriental look. As Peter Brown puts it, we ‘pass from one dominant lifestyle, and its forms of expres sion, to another; [. . .] from an age of equipoise to an age of ambition’.4

Diocletian realized that to remain at Rome would effectively make him a sitting duck. Threats to his power were more likely to materialize in the frontier regions, and for him not to be there in person to deal with them might prove an open invitation to potential usurpers. So his staff (comitatus) and court (sacrum cubiculum) became peripatetic, and he only went to Rome once in his entire reign. He also decided that any aspirations he had towards world domination would need both mortal and divine assistance. So in 285 he named his Illyrian brother-in-arms M. Aurelius Valerius Maxi mianus as Caesar, adopted him as his son, and split up the responsibilities of government: Maximianus was to oversee Italy, Africa, Spain, Gaul and Britain, while Domitian took the Danube and the East. On the divine level, Jupiter and Hercules were integrated into the system. In a speech known as the Second Panegyric for Maximianus, delivered on 21 April 291, an anonymous orator asked:

Shall I rehearse the divine origin of your family, which you attest to not only by your immortal deeds but even by your succession to the name?5

This is an open reference to the fact that Maximianus had taken the name Herculius and Diocletian that of Iovius – they were assimilating the roles of Jupiter (Jove) and Hercules (also father and son) in ruling the universe. The porticos of Pompey’s theatre at Rome were renamed the porticus Iovia and the porticus Herculia in their honour, and some see a parallel here with the Christian belief in God the Father and God the Son.

Diocletian’s role involved touring the Danube and the East: he campaigned in Raetia; installed Tiridates III as King of Armenia; reorganized the Syrian frontier; and fought with the Sarmatians and the Saracens. Maximianus was the junior partner, but he was promoted to Augustus in 286, partly as a reward for crushing some Bagaudae (or Bacaudae: ‘the Warriors’ in Celtic) in Gaul. Some scholars regard the Bagaudae as bands of insurgent peasant-farmers-cum-dispossessed-outlaws driven to brigandage by Roman oppression, although more recent work suggests that they were characters who took over local leadership without Roman authorization, making them bandits or rebels only in the eyes of the Empire. Over the next few years Maximianus beat off the Alemanni and Bur gundiones on the upper Rhine, and got a Frankish chief to make peace in return for being acknowledged as ‘King of the Franks’. Saxon and Frankish pirates in the English Channel posed more of a challenge, and M. Aurelius Mausaeus Carausius may have installed the first elements of a new fortification system in Britain stretching from the Wash to the Solent to guard against them. The forts are still known by the title given them in a document produced in 400 (give or take twenty-five years each way) and preserved in medieval manuscripts known as the Notitia Dignitatum: the Forts of the Saxon Shore.

However, it was Carausius himself who was more of a menace to Diocletian. He was the admiral of the Channel Fleet based at Gesoriacum (modern Boulogne), but he moved across to Britain, proclaimed himself Augustus, and set up a breakaway Imperium Britanniarum rather like Postumus’Imperium Galli-arum. His coinage, which was of a much higher quality than that of the rest of the Empire, tells a fascinating tale: Carausius, Diocletian and Maximianus (in the place of honour), along with the legend CARAVSIVS ET FRATRES SVI (‘Carausius and his Brother Emperors’), appear on the obverse, while Victory as COMES AVGGG (‘the Helper of the 3 Augusti’) is on the reverse. He also issued medallions that bore the letters I.N.P.C.D.A. This is a coded (but obvious to a Roman) reference to a line in Virgil’s 4th Eclogue:

I am nova progenies caelo demittitur alto

Now a new generation is let down from high heaven.6

This is reinforced by the words VICTORIA CARAVSI AVG (‘the Victory of the Emperor Carausius’). It is brilliant PR, and Carausius successfully defied Maximianus until he was assassinated by his right-hand man, Allectus, in 293.

Men United: The Tetrarchy

The year 293 saw a far more significant event, however: the creation of the Tetrarchy (‘Rule of Four’). Diocletian remained the main man and made all the key decisions, but now, in addition to him and Maximianus, the two Augusti, there were to be two Caesares: C. Flavius Valerius Constantius (aka Constantius I Chlorus) and C. Galerius Valerius Maximianus (‘Galerius’). Constantius I Chlorus and Galerius, who were both Illyrians with solid military credentials, were essentially deputies and heirs to Maximianus and Diocletian respectively. The arrangements were cemented by marriage alliances: Constantius I Chlorus was already married to Maximianus’ daughter Theodora, while Galerius wed Diocletian’s daughter Valeria (see Genealogy Table 5). The plan was that theCaesares would ultimately take over as Augusti, and nominate Caesares in their turn. An excellent sculptural representation of the tetrarchs and what they stood for currently stands in St Mark’s cathedral in Venice.7 Made from Egyptian porphyry, it shows the four men in military dress, embracing one another in a manly way and emanating good old-fashioned Roman virtue:

They were indeed four rulers of the world: brave, judicious, affable and exceedingly generous, all of one mind toward the commonwealth, showing great restraint before the Roman Senate, moderate, friends of the people, deeply revered, grave and devout.8

The religious aspect of the regime was underpinned when Diocletian and Galerius formed the Iovii dynasty descended from Jupiter, while Maximianus and Constantius I Chlorus became the Herculii, descended from Hercules.

Each tetrarch was allocated his own comitatus, sacrum cubiculum, troops and sphere of operation:

The Empire was divided into four parts, and all those regions of Gaul which lie across the Alps [i.e., Gaul and Britain] were entrusted to Constantius, Africa and Italy [and Spain and the northern frontier provinces] to Herculius [i.e., Maximianus], the coast of Illyricum right across to the Strait of Pontus [i.e., the Danube territories] to Galerius: Valerius [Diocletian] retained the rest [i.e., the East and Egypt ].9

One crucial consequence of this was that although Rome itself remained important ideologically, the city’s position as the hub of the Empire was fundamentally changed. Each tetrarch resided wherever he happened to be ruling or fighting: Nicomedia, Treveri (modern Trier), Mediolanum, Sirmium, Antioch, Serdica (modern Sofia) and Thessalonica, not to mention Naïssus, Carnuntum and Aquileia. Emperors still invested a considerable amount of money on building projects in Rome, but they themselves visited the place ever more infrequently.

In an attempt to generate an administration that was more in tune with the needs of his subjects, and to curtail the power of individual governors, Diocletian embarked on a root-and-branch reform of the Empire’s organization (See Map 6). At the local level the basic unit remained the city-district (Civitas), but above this some major changes took place. The provinces were reduced in size but increased in number to over one hundred. Lactantius says that this was ‘to ensure that terror was universal’,10 but the goal was more probably to give Diocletian tighter fiscal, legal and administrative control. For instance, Africa now had seven provinces, Hispania six and Britain four: Britannia Prima in the West, including Wales, with its capital at Corinium (modern Cirencester); Britannia Secunda in the north, possibly with Eboracum as the capital; Maxima Caesariensis(probably named after Maximianus) in the south, with its centre at Londinium; and Flavia Caesariensis (named after Constantius I Chlorus) in the East, where the capital may havebeen Lindum (modern Lincoln). Rome’s provinces were all governed by Equestrian praesides, apart from Asia and Africa, where Senatorial Proconsuls held sway. Italy was split into multiple units under Senatorial correctors. On the whole, these men ran the civil administration but seldom exercised military power. This was crucial: uncoupling the army from the civil service meant that governors didn’t control soldiers, and military com manders couldn’t control the ration and salaries of their troops, which greatly reduced the odds of a challenge to the Emperor coming out of the provinces.

Above the provinces came twelve districts called dioceses (sing. diocesis), each ruled by an Equestrian vicarius (‘vicar’) who represented one of the Praetorian Prefects. The Britanniae, for instance, made up one of the twelve dioceses, with its vicarius based at Londinium and responsible to thePraefectus Praetorio of Gaul at Treveri. The other dioceses were: Galliae, Viennensis, Hispania, Africa, Italia, Pannoniae, Moesiae, Thraciae, Asianae, Pontica and Orientis. The Praetorian Prefects were effectively the Emperor’s second-in-command, with less military power but considerable financial, legislative and administrative responsibility. The city of Rome remained outside this system, governed by its Praefectus Urbis (Prefect of the City).

Such a system needed a bureaucracy to make it function properly (even if some modern interpreters feel it was ludicrously top-heavy and a significant factor in the ultimate demise of the Empire). For much of its history Rome had had a minuscule bureaucracy – a few hundred people at the very most – but the Notitia Dignitatum shows that after Diocletian’s arrangements there were now tens of thousands of officials pushing pens and counting beans: a Tribune of the Swine Market in Rome; an Accountant of Private Property in Britain; the eunuchs of the sacrum cubiculum (the ‘Emperor’s Sacred Bedchamber’); ministries of finance (the sacrae largitiones – the ‘sacred largesses’ – and the res privatae – the ‘private affairs’); the quaestor sacri palatii (‘imperial secretary’), backed up by an entire sacra scrinia (‘imperial secretariat’); the agentes in rebus (the imperial couriers between the court and the provinces, and possibly a kind of secret police); and so on. They were powerful people, all with their own staff and plenty of perks, at least if John the Lydian’s tirade against John the Cappadocian, the Byzantine Emperor Justinian I’s Praefectus Praetorio, is sound evidence:

Even as naked pleasure girls were fondling him, other prostitutes would lead him on his way with rampant kisses, leaving him no option but to have sex there and then. Then, when he was spent, he would snatch sweet canapés and drinks from the outstretched hands of other catamites. So many and so sweet and frothy were the drinks, that, when he could no longer keep them down, he just vomited, like a mighty river that has breached its banks, flooding the whole house.11

No wonder a post in the imperial civil service became highly sought after.

The Army, the Economy and the Law

Our written sources also credit Diocletian with, or accuse him of, some of the most far-reaching reforms to the Roman army since Augustus’ day. Lactantius speaks of him

multiplying the armies, as each of the [tetrarchs] strove to have a far larger number of troops than any previous Emperors had had when they were governing the state alone.12

Under Diocletian the army’s strength was increased to some sixty legions, but archaeological evidence shows that legionary fortresses were now much smaller, so estimating the overall size of the Roman army at this time is an inexact science, although figures of around 350 000 to 400 000 men are commonly quoted. The old-school legions of around 5 000 high-quality infantrymen now metamorphosed into something more flexible. The legions, auxiliary cavalry alae and cohorts of this ‘New Model Army’ now functioned alongside other units sometimes vaguely designated numeri(‘numbers’) while the cavalry of the field armies were organized into vexillationes. Overall the army was now divided into a central mobile field force (comitatenses, ‘companions’) commanded by magistri militum, and static frontier garrisons (ripenses – riverside troops, referring to the Rhine and Danube – and limitanei, ‘borderers’) commanded by duces (Dukes, sing. dux). Limitanei who became permanently attached to one of comitatenses were designatedpseudocomitatenses. There was a hierarchy descending from the imperial guards (the scholae and the domestici), down to the elite ‘palatine’ units (palatinae), the ‘praesental’ field armies (those ‘in the presence of’ the Emperor), the regional field armies, and thelimitanei, who got less pay and fewer privileges than the comitatenses, but still seem to have operated pretty effectively as a rule.

The basic kit of the Roman infantry came to be trousers and a shortish, long-sleeved tunic, belted at the waist. Belt buckles and the brooches that fastened their cloaks served as the badges of the different ranks. Armour comprised a mass-produced helmet, scale or mail body armour rather like the medieval hauberk but with sleeves and a hood, plus a circular or oval shield sporting the regimental insignia. Offensive weaponry included a sword called a spatha (longer than the old gladius), various combinations of thrusting- and throwing-spears (the spiculum – rather like a pilumverutum and lancea), and lead-weighted darts called plumbatae or mattiobarbuli. Archers, slingers and manuballistae (cart-mounted catapults) were also deployed. The cavalry arm featured heavily armouredclibanarii and cataphracti, especially in the East, as well as lighter armed scutarii,promoti, stablesiani, mounted archers and units of Moors and Dalmatians.

All this, especially the trousers and long swords, had a somewhat ‘barbarian’ flavour to it. The duces were often of non-Roman stock, as is shown by names like Fullofaudes, Duke of Britain; the Notitia Dignitatum calls the workshops that produced ornamented armour barbaricaria; the later imperial army also adopted the draco, a sort of windsock in the form of a dragon, which the Dacians on Trajan’s Column used as a standard; the units of the field army started to assume somewhat ‘barbarous’, almost animalistic, titles; and the war cry, the barritus, was often, if mistakenly, said to have a barbarian origin.13

In addition to the deployments of troops, Diocletian shored up the frontiers by installing fortresses (castella) and small forts (burgi), reinforcing natural barriers and constructing military roads. Needless to stay, this was very expensive – so much so that it is thought that around 66 per cent of GDP went into maintaining the army – and with this in mind the tetrarchs set out to regularize the tax system. They opted for assessments based on income in kind. The fiscal value of everybody’s property was calculated in terms of iuga (land units of varying size depending on their productivity) and capita (‘heads’, poll-tax calculations), although the terms are broadly interchangeable. An edict by Aurelius Optatus, the Prefect of Egypt, shows the measures being introduced:

Accordingly, seeing that in this too they have received the greatest benefaction, the provincials should make it their business in conformity with the divinely issued regulations to pay their taxes with all speed and by no means wait for the compulsion of the col lector.14

The whole system was backed up by a regular five-yearly census so that the government could budget properly for the future. This may have been economically effective, but like any hardline tax collection measure it was unpopular.

Diocletian also tried to confront problems to do with the coinage and inflation by minting well-struck gold coins at a standard rate of sixty coins to the libra (pound) of high-quality metal, and similarly good silver ones, some of which were marked XCVI (i.e., ninety-six coins to the libra of silver) to signify their worth. In 301 there was a reform in which most coins seem to have had their value increased by 100 per cent, presumably in an attempt to keep pace with inflation, and this was followed two months later by the well-known Edictum de Maximis Pretiis (‘Maximum Price Edict’), which sought to prevent profiteering on foodstuffs, goods and services. For instance, wheat was not to exceed 100 denarii per army modius, barley 60 or salt 100; first-quality aged wine was capped at 24 denarii per sextarius, Pannonian beer at 4 and Egyptian beer at 2; pork was limited to 12 denarii per Italian pound, beef to 8, butter and second-quality fish to 16. In terms of wages, a farm labourer or sewer cleaner got no more than 25 denarii per day, a carpenter 50, a shipwright working on a seagoing vessel 60, and a wall painter 75. Vets got 6 denarii per animal for clipping and preparing hooves, barbers 2 per man, scribes 25 for 100 lines of best writing, teachers of arithmetic 75 per boy per month, teachers of Greek or Latin language and literature 200 per pupil per month, and an advocate 1 000 per case. Transgressions were punishable by death, at least in theory, but the law seems to have been both unpopular and ineffective:

Diocletian [. . .] tried to fix by law the prices of goods put up for sale. Much blood was then shed over small and cheap items, and in the general alarm nothing would appear for sale; then the rise in prices got much worse until, after many had met their deaths, sheer necessity led to the repeal of the law.15

Inflation would soon be a problem once again.

One rather more successful process that occurred in Diocletian’s reign concerned the codification of Roman law. The laws of Rome were effectively made up from the rulings that the various Emperors had made over the centuries, and in around 292 some sixteen books of these, dating back to the mid-second century, were published by a certain Gregorianus, who was perhaps Domitian’s magister libellorum (Master of Petitions), in the Codex Gregorianus. It was then supplemented by the Codex Hermogenianus, published in 295 by another magister libellorum called Aurelius Hermogenianus, who was really the first lawyer to try to distil the law down to a small number of key principles from which solutions to issues could be worked out. The term codex, which originally means ‘a paged book’, came to designate a code in the sense of ‘a collection of imperial laws’.

Challenges from Within and Without

Diocletian had to face direct challenges to his authority from inside the Empire. In 297 a revolt broke out in Alexandria led by L. Domitius Domitianus and Aurelius Achilleus (if the two men are not in fact one and the same), but Diocletian managed to suppress it after a long siege which he conducted in person. More concerning was the threat coming from Allectus in Britain. Having murdered the ‘third Augustus’ Carausius in 293,16 he remained at large until Constantius I Chlorus mounted a seaborne invasion against him in 296. The Praefectus Praetorio Asclepiodotus eluded Allectus’ fleet in a mist, landed on the south coast and defeated his army near Calleva Atrebatum (modern Silchester), while Constantius’ forces sailed up the Thames and entered Londinium as liberators. The Bibliothèque nationale de France has a superb solid gold medallion that was struck at Treveri to commemorate the event. It depicts the conquering hero approaching the gates of the city and being greeted by a kneeling female personification of London (the only pictorial representation of Roman London yet to be found) while a warship full of soldiers sails up the Thames. Constantius is on the obverse along with the key message REDDITOR LVCIS AETERNAE (‘the Restorer of Eternal Light’); the light of Roman civilization shines over Britain again; the unity of the Empire is restored.

The tetrarchs certainly had to fight their corners, but they did so with some success: Constantius I Chlorus prevailed in fierce strife against the Alemanni; Maximianus triumphed over the Quinquegetani in Africa; and Diocletian and Galerius conquered the Bastarnae, the Iazyges and the Carpi, and then settled large numbers of them on Roman soil. In the East the new Persian king, Narses, resurrected Shapur I’s imperialist ambitions and incited uprisings by the Blemmyae in Egypt and the Saracens in the Syrian desert. Diocletian dealt with the Egyptian problem easily enough, but an invasion of Armenia, Osrhoene and part of Syria by Narses was more problematical. Galerius initially suffered a defeat near Carrhae, but then comprehensively destroyed Narses’ forces in 298, captured Ctesiphon, reinstalled the pro-Roman (and later Christian) Tiridates III in Armenia, extended Rome’s possessions beyond the Tigris, and most importantly secured peace in the region for several decades. In a results-based world, the tetrarchy was doing very nicely.

The Great Persecution

To commemorate his victory over Narses, Galerius commissioned a triple arch, which was integrated into his palace complex at Thessalonica. Its sculptural panels depict Galerius subduing Narses in hand-to-hand combat, and elsewhere winged Victories place wreaths on the heads of the twoAugusti, who sit enthroned above two figures that may represent heaven and earth, while female captives are brought to them. Their two Caesares and various supporting gods complete the image. This is illuminating: maintaining thepax deorum, the peace of/with the gods, was one of any Emperor’s key jobs. The Romans felt strongly that piety guaranteed the security of the State, and conversely there was zero tolerance for any religious subversiveness that might alienate the gods.

Symptomatic of this mindset is Diocletian’s Edict Against Manichaeism. Manichaeism had been founded by a Babylonian prophet called Mani in the middle of the third century. The cult offered redemption, and would become an important religion in due course, but for now it was persecuted by both the Persian and the Roman authorities. In around 297 the tetrarchs wrote to the Proconsul of Africa. They were concerned that ‘the accursed customs and perverse laws of the Persians’ might ‘infect men of a more innocent nature, namely the temperate and tranquil Roman people’:

They lure on many others to accept the authority of their erroneous doctrine. But the age-old religion [ought not to] be disparaged by a new one. For it is the height of criminality to re-examine doctrines once and for all settled and fixed by the ancients [. . .] Now, therefore, we order that the founders and heads be subjected to severe punishment: together with their abominable writings they are to be burned in the flames. We instruct that their followers, and particu larly the fanatics, shall suffer a capital penalty, and we ordain that their property be confiscated.17

It was in a similar context to this that Diocletian unleashed the Great Persecution against the Christians in 303. According to Lactantius, the trigger was a sacrifice at which the haruspices, who checked out the entrails of sacrificial victims, could not find any favourable omens and blamed the Christians who were present. Yet for Diocletian to take an anti-Christian stance seemed odd, given that he had no prior form for this and that his wife, Priscia, was Christian (or at least well disposed to Christians), and Lactantius makes Galerius the driving force behind the events, under the influence of his pagan-fundamentalist mother. To confirm that he was doing the right thing, Diocletian sent a haruspex to the oracle of Apollo at Didyma. The question is not recorded, but the answer was explicit: persecute the Christians. An indirect report of the consultation also appears in a letter written by the Emperor Constantine, who was eighteen years old at the time, and must have relied on a rather convoluted oral tradition:

About that time it is said that Apollo spoke from a deep and gloomy cavern, and through the medium of no human voice, and declared that the righteous men [i.e., the Christians] on earth were a bar to his speaking the truth, and accordingly that the oracles from the tripod were fallacious. Hence it was that his priestess, letting her locks flow down and driven by madness was lamenting this evil among men.18

Constantine and his informants wrongly thought Apollo’s response came from Delphi; there was no oracular cave at Delphi or Didyma; contrary to popular belief the priestess did not go into a frenzy;19 and no one at Delphi or Didyma ever claimed that the oracular words came directly from the god himself. As with many second-hand reports about oracles, this all looks very circumstantial.

On 23 February 303, at the Roman festival of the Terminalia, the church at Nicomedia was ransacked, and the next day the first Edict Against the Christians was published. Its precise wording is not preserved, although it probably sounded rather like the Edict Against Manichaeism, and Eusebius gives us the gist:

An imperial decree was published everywhere, ordering the churches to be razed to the ground and the Scriptures destroyed by fire, and giving notice that those in places of honour would lose their places, and domestic staff, if they continued to profess Christianity, would be deprived of their liberty. Such was the first edict against us. Soon afterwards other decrees arrived in rapid succession, ordering that the presidents of the churches in every place should all be first committed to prison and then coerced by every possible means into offering sacrifice.20

When Diocletian fell seriously ill in 304, Galerius issued another Edict that forced Christians to choose sacrifice or death. After Diocletian retired, the process was continued by Maximinus Daia, Galerius’ Caesar, who issued further Edicts in 306 and 309, until Galerius made a deathbed repentance in 311, stopped the persecution and granted Christians legal recognition.21 Maximinus Daia made one last attempt at a pagan revival in 311–312:

Who is so obtuse as not to see that the benevolent concern of the gods is responsible for the fertility of the earth, for keeping the peace, and defeating unrighteous enemies, for curbing storms at sea, tempests and earthquakes, which have only occurred when the Christians with their ignorant and futile beliefs, have come to afflict almost the whole world with their shameful practices.22

Ultimately the Emperor Constantine put a stop to this. Christianity was simply becoming too well-established in both the rural and the urban environments, particularly in the East, and the horrendous violence was also alienating many pagans who did not necessarily harbour the prejudices that their rulers did.

Saints George, Sebastian, Erasmus (Elmo), Vitus and Catherine are all associated with Diocletian’s persecution, along with perhaps as many as 3 500 other victims. Eusebius escaped, though, and wrote eloquently and emotionally about the events in his Church History. In fact, the Edicts were not consistently enforced: in Italy Maximianus was zealous to start with, but soon backed off, while in Gaul Constantius I Chlorus just went in for some desultory church destruction, if that. Nevertheless, the Great Persecution was incredibly distressing, and etched itself very deeply into the Christian psyche.

Power Struggles and the Rise of Constantine

Diocletian had always intended that the Augusti should abdicate, and once he and Maximianus had celebrated twenty years of rule, that is what happened. On 1 May 305, they gave up their powers (Maximianus rather unwillingly), to be replaced by their CaesaresGalerius and Constantius I Chlorus. Since Diocletian had no direct heirs, the question of who would become the new Caesares was sensitive. There were dynastic options in the persons of Maximianus’ son Maxentius and Constantine, Constantius’ illegitimate son by Helena, a Bithynian barmaid (or, in British legendary tradition, an Essex girl). 23 But Diocletian had other ideas. He opted instead for Flavius Valerius Severus, an Illyrian friend of Galerius, as Caesar to Constantius in the West, and C. Galerius Valerius Maximinus Daia, as Caesar to his uncle Galerius in the East. With Constantius controlling Britain, Gaul and Spain, Severus in possession of Africa, Italy and Pan nonia, Galerius ruling Asia Minor west of the Taurus Mountains, and Maximinus in charge of the other Asiatic provinces and Egypt, Diocletian retired to his humungous fortified palace at Spalato (modern Split, in Croatia), where he remained, contentedly growing vegetables, until his death.

Our sources make it very difficult to establish a clear political and chronological picture of the events of the next few years, but it is clear that in 306 Constantius I Chlorus returned to Britain to command a major onslaught against the Picts in the north. He secured Galerius’ permission to allow his son Constantine to accompany him, but died at Eboracum shortly after his victory. Constantine, who had probably been born around 273 at Naïssus in Moesia Inferior, was immediately proclaimed Augustus. This transgressed the ethos of the tetrarchy. An Augustus was supposed to be replaced by his Caesar (Severus was first in line), but Constantine informed everyone about his ‘forced’ elevation, moved across into Gaul, cemented his popularity with his troops by defeating the Alemanni and the Franks and throwing their kings to wild beasts in the arena, and waited for the other Augustus Galerius’ reaction.

The uncertainty now gave an opportunity for Maximianus’ son Maxentius to throw his hat into the ring by exploiting some unrest in Rome, getting himself nominated as Princeps (an old-fashionedly vague designation) and bringing his father Maximianus out of retirement. Galerius’ response was to make Severus march on Rome, but Maximianus, who was now calling himself Augustus as well, pushed Severus back to Ravenna and captured him. Severus was duly put to death. Maxentius now joined the expanding list ofAugusti as well.

Needing to bolster himself against the predictable forthcoming backlash from Galerius, Maxentius turned to Constantine. In return for reciprocal acknowledgements of Augustus status, Maxentius gave Constantine his sister Fausta in marriage. Galerius got as far as Interamna but did not have the wherewithal to storm the walls of Rome, so he had to back off. Maxentius must then have been appalled to find that is own father had tried to talk Constantine into attacking both himself and Galerius. Constantine was not prepared to do this, so Maximianus had to do his own dirty work: he went to Rome, but when he ripped Maxentius’ purple robe from his shoulders the soldiers intervened. Maximianus sloped off to Constantine; Maxentius maintained control of Rome.

With the tetrarchic system in tatters, Galerius sought a diplomatic solution by asking Diocletian to chair a conference at Carnun tum that was held in November 308. Maximianus also attended, but Maxentius was excluded and outlawed. Diocletian preferred his green fingers to the imperial purple, but he did talk Maximianus into retiring. Licinianus Licinius, an experienced general and comrade of Galerius, succeeded Severus as the junior of the two Augusti, and was given Italy, Africa and Spain, despite the fact that Maxentius actually controlled them; Maximinus Daia carried on as Caesar as before; and Constantine was relegated to Caesar of Gaul and Britain. However, the egos of the two Caesares were not satisfied by this, and Galerius was forced into making them Augustiquite soon afterwards.

So now there were four Augusti: Galerius based at Thessalonica; Licinius at Sirmium; Constantine at Treveri, and Maximinus Daia at Antioch. Just to make things interesting there was also Maxentius claiming to be Augustus and the ex-vicarius of Africa doing the same under the grandiose title of Imperator Caesar Lucius Domitius Alexander Pius Felix Invictus Augustus. Gradually, though, various contenders fell by the wayside. In 310 a series of intrigues ended with Maximianus dead, and Constan-tine, if not directly responsible, at least pleased about it. The following year one of Maxentius’ Praetorian Prefects dispatched Domitius Alexander, and Galerius died horribly:

Without warning, suppurative inflammation broke out round the middle of his genitals, then a deep-seated fistular ulcer: these ate their way incurably into his inmost bowels. From them came a teeming indescribable mass of worms, and a sickening smell was given off; for the whole of his hulking body, thanks to overeating, had been transformed even before his illness into a huge lump of flabby fat, which then decomposed and presented those who came near with a revolting and horrifying sight.24

Galerius attributed this to the wrath of God for persecuting the Christians, repented just before he died, and issued an Edict of Toleration. Lactantius wanted to portray Galerius’ fellow persecutor Diocletian as meeting a similarly exemplary fate, and says that he starved himself to death in 311 or 312, although Diocletian may in fact have lived longer. Constantine, meanwhile, was looking in a different direction for divine backing, and started to put forward the notion that his father, Constantius I Chlorus, was descended from Claudius II Gothicus, while an anonymous panegyric from 310 talks of him having a vision:

You saw, Constantine, I believe, your own Apollo, accompanied by Victory, offering you a laurel crown, signifying three decades of rule.25

Constantine’s coins now start to show Sol Invictus, the sun god, with whom Apollo was identified: he was moving away from his Herculean roots.

Events were moving towards their climax. Constantine came to an accommodation with Licinius, while Maxi minus Daia threw in his lot with Maxentius. As Licinius and Maximinus Daia cancelled each other out in the East, Constantine took a huge risk and bore down on Maxentius in Italy, but he offset his numerical disadvantage by acting decisively. Having crossed the Alps, he scored a victory near Augusta Taurinorum (modern Turin) over a force that included some formidable clibanarii, received the surrender of Mediolanum, and again defeated Maxentius’ forces at Verona. At Rome Maxentius prepared to resist a siege, but for some reason he had a change of heart and decided to settle things in open combat. On 28 October 312 he led his men out over the Tiber across the Pons Milvius (Milvian26 Bridge) for a battle that would decide the future of Europe.

1   Tr. Bird, H. W., op. cit. Aurelius Victor writes that Diocletian was intelligent, sensible and experienced, but a bit uncivilized; the Historia Augusta, Carus, Carinus and Numerian says he was shrewd, focused, prudent and loyal; the Christian Lactantius calls him a perpetrator of mischief and criminality.

2   Halsall, G., Barbarian Migrations and the Roman West, 376–568, Cambridge: Cambridge University Press, reprinted with corrections, 2009, p. 65. Halsall is mainly discussing the influential view of A. H. M. Jones in his important work The Later Roman Empire. A Social, Administrative and Economic Survey, Oxford: Basil Blackwell, 1964.

3   Aurelian had already taken steps in this direction (see above, p. 283 f.), but Diocletian’s reign represents the culmination of the process.

4   Brown, P., The Making of Late Antiquity, Cambridge, MA, and London: Harvard University Press, 1978, p. 34.

5   Panegyrici Latini XI [3], 2.3, tr. Mynors, R.A.B., in Nixon, C.E.V. and Rodgers, B. S., In Praise of Later Roman Emperors: The Panegyrici Latini. Introduction, Translation and Historical Commentary. Transformation of the Classical Heritage vol. 21, Berkeley: University of California Press, 1994. Cf. VII [6], 8.2; IX [5], 8.1.

6   Virgil, Eclogues 4.7, tr. Kershaw, S.

7   It was probably first erected in Nicomedia, but found its way to Constantinople, where it came to be called Philadelphion (‘Brotherly Friendship’). It was looted by Crusaders in 1204, and taken to Venice.

8   Historia Augusta, Carus, Carinus and Numerian 18.4, tr. Kershaw, S.

9   Aurelius Victor, de Caesaribus 39.30, tr. Bird, H. W., Aurelius Victor, De Caesaribus, Translated with an Introduction and Commentary by H. W. Bird, Liverpool: Liverpool University Press, 1994.

10   Lactantius, On the Deaths of the Persecutors 7.4, tr. Fletcher, W., op. cit.

11   John the Lydian, De Magistratibus Reipublicae Romanae 3.65, tr. in Moorhead, S. and Stuttard, D., AD 410: The Year That Shook Rome, London: British Museum Press, 2010, p. 34.

12   Lactantius, On the Deaths of the Persecutors 7.2, tr. Fletcher, W., op. cit.

13   See, e.g., Ammianus Marcellinus 26.7.17; Speidel, M. P., Ancient Germanic Warriors: Warrior Styles from Trajan’s Column to Icelandic Sagas, London and New York: Routledge, 2004, pp. 101 ff.

14   P. Cairo Isidore 1, tr. in Lewis, N. and Reinhold, M. (eds), op. cit., p. 419.

15   Lactantius, On the Deaths of the Persecutors 7.6 f., tr. Fletcher, W., op. cit.

16   See above, p. 294.

17   Comparison of Mosaic and Roman Law 5.3, tr. in Lewis, N. and Reinhold, M. (eds), op. cit., p. 549.

18   Constantine, ap. Eusebius, Life of Constantine 2.50, tr. Richardson, E. C., in Schaff, P., and Wace, H., The Nicene and Post-Nicene Fathers of the Christian Church, Second Series, Vol. I, Eusebius Pamphilus: Church History, Life of Constantine, Oration in Praise of Constantine, Edinburgh: T & T Clark, 1890.

19   See Kershaw, S., op. cit, 2010., pp. 151 ff.

20   Eusebius, Church History 8.2, tr. Williamson, G. A., in Eusebius: History of the Church, London: Penguin Classics, 1989.

21   Lactantius On the Deaths of the Persecutors 33.11–35.1; 24.9; 8.14.1; Eusebius, Church History 8.16.1; 17.1–11; 8.14.1. See below, p. 309.

22   Eusebius, Church History 9.7.8–9, tr. Williamson, G. A., op. cit.

23   See Harbus, A., Helen of Britain in Medieval Legend, Cambridge: D.S. Brewer, 2002.

24   Eusebius, Church History 8.16, tr. Williamson, G. A., op. cit.

25   Panegyrici Latini VII [6].21, tr. Mynors, R. A. B., op. cit. The three decades were symbolized by the figure XXX.

26   Also interchangeably spelled Mulvius/Mulvian.

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