Diocletian’s New Roman Empire
In the course of the 290s, Diocletian transformed the Roman empire beyond recognition. A governmental revolution grew out of the emergency measures which Diocletian undertook piecemeal in order to keep himself secure on his throne. The cumulative effect of such measures was enormous. It removed many of the systemic causes of disorder that had plagued the third-century empire, and thereby created the powerful Roman state with which the fourth-century Goths had to deal. As we have seen, the first important step that Diocletian took was to appoint Maximian as his fellow augustus, or co-emperor, in 285. The point of this measure was to multiply the imperial ability to deal with many different threats at one time. An emperor who was on the spot and seen to be doing his job was a powerful disincentive to usurpation by a local governor or general. Diocletian took this principle still further, by appointing two junior emperors, called caesars, as a complement to the two senior augusti. Together, these four emperors would form an imperial college in which the actions of each emperor would symbolically be the actions of all four: a law issued by one emperor was issued in the name of all four, and when one emperor won a victory, all four took the victory title associated with it. This college of four emperors is known to scholars as the tetrarchy (‘rule of four’ in Greek). For as long as it lasted, the new tetrarchy of Diocletian and Maximian, with their caesars Constantius and Galerius, ensured that an emperor was on hand in nearly every trouble spot of the empire, ready to suppress a looming threat and thereby discourage any local response that might challenge the hold of Diocletian and his colleagues on their thrones. The tetrarchic system was also meant to ensure a smooth succession, as a caesar would be waiting to succeed a senior augustus should the need arise.
Diocletian’s reform of the imperial office was accompanied by an elaborate religious ideology that assigned to the ruling emperors divine descent from Jupiter and Hercules, those gods that were most ostentatiously Roman in the traditional pantheon. The tetrarchy also insisted on renewed attention to the imperial cult – the worship of past, deified emperors and of the genius, or protecting spirit, of the living emperor. Both measures were designed to ensure that the gods would smile on and protect the empire. The famous Diocletianic persecution of Christians, widely known as ‘the Great Persecution’, was a consequence of this tetrarchic ideology, because Christians refused to worship any god but their own and by doing so might endanger the health of the state. If religion was one basis on which Diocletian rested his authority, he took other measures as well, reforming the currency, expanding the army, and re-enforcing the elite guard units that traveled with the emperor. Most importantly, he broke up the very large provinces of the early empire into more than a hundred smaller provinces, while also separating the military and civilian hierarchies in the imperial government. The first measure dramatically reduced the scale of any one official’s command, while the second meant that the officials who collected taxes and disbursed state salaries to the soldiers were not the same officials who commanded the troops in the field. Together, both measures undermined the ability of either military or civilian officials to claim the imperial throne for themselves. As we have said, the various Diocletianic reforms were ad hoc measures, meant to deal with the many different problems that had afflicted the third-century empire. Yet as a group, they were revolutionary: they not only allowed Diocletian to hold his throne for more than two decades, they also produced a system of government that remained effective even after the tetrarchy itself broke down. In other words, the type of imperial goverment originally outlined by Diocletian and the tetrarchy was in essence the same one with which Alaric had to deal a hundred years later. More important for our immediate purposes, however, Diocletian’s reforms meant that for the first time in over half a century, a Roman emperor was secure enough on his throne to deal effectively with barbarians beyond the northern frontier – with serious consequences for the Goths.
The Tetrarchs and the Northern Frontiers
This new imperial strength meant that the constant stream of frontier wars slackened considerably in the years before 305, when the augusti Diocletian and Maximian abdicated and passed the senior title on to their caesars Constantius and Galerius, who then appointed two new caesars to serve as their junior emperors. Instead of constantly reacting to events beyond their control, the tetrarchs were increasingly able to decide when and where they wanted to fight along their frontiers. They began to co-opt powerful barbarian leaders into imperial circles, and to manage the affairs of their barbarian neighbours in what they perceived as the best interests of Roman power. This policy can be inferred from obscure, but clearly very important, disturbances along the lower Danube in the 290s and early 300s. We saw in chapter one how Diocletian won a victory over one group of Goths, the Tervingi, as the panegyric of 291 attests. We do not know what prompted the campaign that led to that victory, but the decade that followed seems to have witnessed the substantial growth of Tervingian power. Although this Gothic expansion is not attested by positive evidence, it can be inferred from other known events, most importantly the displacement of an older barbarian grouping. Sometime before early 307, Galerius fought a campaign against the Sarmatians, which is to say in the region between the Danube and the Tisza rivers. Then, in the summer of 307, he attacked the Carpi further east, settling a very large number of them in a Roman province south of the Danube as defeated subjects of the empire.[54]
The willingness of the Carpi – virtually all of them, it seems – to be removed from a territory in which they had dwelt for well over a century is significant. It suggests that the military pressure of a neighbouring barbarian power had become too great for them to sustain and that their attempts to find refuge in the empire had provoked a punitive imperial campaign. The Gothic Tervingi are the barbarian group most likely to have affected the Carpi in this way. We seem, in other words, to see an increasingly powerful Tervingian polity near the mouth of the Danube extending its power at the expense of its immediate neighbours, perhaps with the tacit support of the imperial government. That support can probably be inferred from the fact that the tetrarchs fought no campaigns against the Tervingi after 291. On the contrary, Goths may have been recruited into the imperial army and served with Galerius in Persia, though the only evidence comes from Jordanes and is therefore suspect.[55] It is thus quite likely that the tetrarchs were complicit in the build-up of Tervingian power, viewing them as a favoured barbarian group which could help keep in check other barbarians further up the course of the Danube.
There was a real logic to that approach. While the lower Danube was consistently under the firm control of an emperor resident in the Balkans (first Galerius, then Licinius), the provinces of the middle and upper Danube were the usual setting for confrontations between rivals in the years after 305. Because this imperial preoccupation with the upper and middle Danube lasted for a full two decades after 305, imperial support of Tervingian hegemony in this period is quite plausible. It would, moreover, allow us to make sense of two massive ditch-and-rampart wall systems which were built around this time in Bessarabia and Galatz, well beyond the imperial frontiers. Like the long east-west wall system known as the Csörsz-árok, built beyond the Pannonian frontier in modern-day Hungary, these fortifications are of a quality and on a scale that could not have been attained without imperial approval. From the imperial point of view, it would be useful to have a reliable Gothic ally keeping the lower Danube quiescent. By favouring the Tervingi, allowing fortifications to be built in their lands on such a scale, their strength and security could act as an additional layer of imperial defence, allowing emperors to focus on more immediate threats elsewhere. Imperial support along these lines explains why the Tervingi are so much more powerful when we next meet them in our sources, around the year 320.
The Breakdown of the Tetrarchy
In the meantime, however, the tetrarchic experiment had broken down entirely. Diocletian and Maximian abdicated in 305, for reasons that
remain extremely controversial. Galerius and Constantius became augusti, but the choice of new caesars caused problems. Rather than the sons of Maximian and Constantius, who had long been groomed for the succession, two of Galerius’ close supporters were appointed as caesars. Before long, however, both the imperial children had seized the purple for themselves. After his father died at York in 306, Constantine was acclaimed emperor, supposedly at the instigation of the Alamannic king Crocus, a client of the late Constantius and an early example of a barbarian noble holding a high position in the imperial army.[56] Maxentius, the son of Maximian, was proclaimed emperor at Rome in the same year, with the support of the Roman populace. Constantine’s proclamation was soon recognized by the senior augustus Galerius, but Maxentius was never accepted as a legitimate emperor. For half a decade between 307 and 313 the Roman empire was wracked with civil wars that gradually eliminated most of the key claimants to the imperial title. By 313, there were only two emperors left, Constantius’ son Constantine (r. 306–337), now a fervent Christian, in the West, and Licinius (r. 308–324), an old comrade of Galerius, in the East. Despite their violence, the civil wars of 307–313 demonstrate the basic solidity of the Diocletianic reforms, because the hallmarks of the third-century crisis are entirely absent from the post-tetrarchic conflicts: no provincial general made an opportunistic bid for the throne, no provinces broke away under their own imperial succession, and no barbarian kings exploited the situation to launch a major invasion across the frontiers.
Indeed, a firm hand was kept on the imperial frontiers despite active civil war. Even before they had done away with other rivals, Constantine and Licinius between them controlled most of the Rhine-Danube frontier. Both undertook traditional imperial campaigns into the barbaricum, Constantine leading Frankish kings in triumph at Trier, Licinius attacking Sarmatians near the Danube bend.[57] As always, we cannot know precisely what prompted the individual campaigns, but the perpetual demand for imperial victories, combined with a need to control barbarian politics while preparing for internal Roman conflict, can explain most of the fighting. A similar calculation probably lies behind the momentous propaganda decision which Constantine took in 310. In the old tetrarchic ideology, Constantius had been the adoptive son of Maximian, and hence took on his adoptive father’s putative descent from the god Hercules, along with the name Herculius that represented it. In 310, however, Constantine repudiated the Herculian name which he had inherited from Constantius. He instead began to claim descent from the emperor Claudius Gothicus, a fiction first attested on 25 July 310.[58] It made sense for Constantine to rid himself of the old Herculian connection after his final break with Maximian and Maxentius in 310, but there may have been more to it than that. Claudius, one of the third century’s great military heroes, won his Gothic victories in the Balkans. Constantine’s claim to a Claudian descent may be the first indication of the Balkan ambitions he was to demonstrate before too long.
Constantine and Licinius
Between 313 and 316, Constantine and Licinius maintained the cordial neutrality that had allowed them to work together during the last years of the civil wars, but their truce was uneasy and they came to blows in 316. The western Balkans fell to Constantine in this war. He took over Licinius’ residence at Sirmium, dividing his time between that city and Serdica, and leaving his son and caesar Crispus in Trier to guard the Rhine frontier and campaign against the Franks and Alamanni.[59] Constantine’s eastern ambitions were now clear, as his choice of residence could hardly fail to demonstrate, and he used the old tactic of disciplining the barbarians to provoke a final confrontation with Licinius. In 323, Constantine campaigned against the Sarmatians on the frontiers of Pannonia, winning one battle, over a king called Rausimod, at Campona in the Pannonian province of Valeria, and a second considerably further downstream at the confluence of the Danube and Morava in Moesia Superior.[60] Coins issued at Trier, Arles, Lyons and Sirmium celebrated the success with the legend Sarmatia devicta (‘Sarmatia conquered’) and Constantine took the victory title Sarmaticus.[61] He may also have instituted new celebratory gladiatorial games, as an epigraphic reference to ludi Sarmatici, Sarmatian games, suggests.[62] Regardless, the campaigns were a provocation of Licinius, into whose territory Constantine had marched while attacking the Sarmatians. Almost certainly intentional, this violation of his fellow emperor’s sovereignty led to the final break between Constantine and Licinius – the latter supposedly melting down Constantinian gold coins celebrating the victory in order to make the point as publicly as possible.[63]
In the ensuing civil war, both sides made substantial use of barbarian soldiers. Licinius had won a victory over the Goths before 315 and peace terms may have included Gothic service in his army.[64] In the war against Constantine, Goths fought on the side of Licinius, probably under a general named Alica. Constantine had used Frankish auxiliaries in his earlier campaigns and by the time of the war with Licinius, the Frankish general Bonitus had reached a position of rank in Constantine’s army.[65] As we have seen, barbarians had always served in imperial armies, but there is some reason to think that the build-up to war between Constantine and Licinius represents a new phase in this phenomenon. For one thing, the early 320s were the first period since the onset of military crisis in the third century during which rival emperors had ample leisure to recruit troops for themselves. For another, both Constantine and Licinius were competing for roughly the same pool of manpower, that is to say, barbarians from the middle and lower Danube – Sarmatians and Goths, generically “Scythians” – and such competition almost always increases both supply and demand. This increasing reliance on barbarian recruits is partly hypothetical, but is probably confirmed by the testimony of the Caesares, a satire on his predecessors written by the emperor Julian, which is scathing about Constantine’s recruitment and subsidy of barbarians.[66] Certainly, as the fourth century progressed, emperors made more and more use of barbarians in filling up the ranks of the army. That being the case, it seems likely that the precedent set by Constantine and Licinius in the early 320s was validated by its very success: Constantine routed Licinius.
Constantine and the Danube Frontier
That victory allowed Constantine a free hand in the Balkans, which he used partly for grandiose construction schemes. The manpower which these projects required is attested by a dramatic increase in the region’s supply of bronze coinage in the late 320s. In the valley of the Porecka near the Iron Gates, a major wall system was put up to control threats from across the river. That was eminently practical, but a more spectacular venture was a new bridge over the Danube from Oescus to Sucidava, which in 328 established a real and a symbolic bridgehead onto what one source now calls the ripa Gothica.[67] Constantine also continued the tetrarchic program of constructing quadriburgia along the Danube. These small forts, enclosing less than one hectare, were a new development of the early fourth century. They were characterized by a tower at each of their four corners (hence their name), and were built both on the right bank of the river in the Roman provinces of Moesia Secunda and Scythia, and also on the barbarian left bank. Primarily useful for keeping the barbarians under observation, quadriburgia could also serve as advance posts for Roman military action. Although the whole Danube frontier received this sort of imperial attention, the lower stretch of the river, and hence presumably the Tervingi beyond it, was the main focus. Thus in parallel to the Oescus-Sucidava bridge, Constantine built a new quadriburgium at Daphne, on the left bank of the Danube across from Transmarisca. How should we account for this focus on the stretch of the Danube opposite the lands of the Gothic Tervingi? Perhaps the most obvious explanation is the fact that Goths had fought on Licinius’ side in the recent civil war. But the support which the tetrarchs and Licinius seem to have given to the rise of Tervingian power in the region probably also worried Constantine.
Constantine’s Gothic War
The later 320s witnessed a series of disturbances beyond the Danube frontier which may have just
ified such worries. As with the displacement of the Carpi twenty years earlier, these events can be understood in terms of Tervingian threats against their neighbours. First, in 330, a number of Taifali invaded the Balkan provinces, perhaps driven there by the Tervingi.[68] A request for imperial aid from some of the Tervingi’s Sarmatian neighbours soon followed, and developed into a major Gothic war. The Sarmatians had long been subject to the usual Roman mixture of subsidy and punishment. The remains of the large Sarmatian defensive systems just to the east of the Danube bend – most famously the Csörz-árok mentioned earlier – were undoubtedly built with Roman permission and suggest the sort of alliance that would have justified the Sarmatians’ request for assistance. The extent of Gothic power is revealed by the response to this request. Constantine launched a campaign against the Goths, the first stage of which was won ‘in the lands of the Sarmatians’, thus beyond the Pannonian section of the Danube frontier.[69] That implies a range of Gothic military action far away from the point where the Goths had hitherto appeared in our sources.
One must surmise that, in the aftermath of Constantine’s victory over Licinius, and while he himself was distracted by internal political problems, a Tervingian king had seized the opportunity to expand his hegemony at the expense of barbarian neighbours, although without directly threatening a Roman province. Probably he expected events of the previous two decades to repeat themselves: his defeated enemies would be accepted into the Roman empire and settled there, while he would be allowed to continue expanding his control in the trans-Danubian lands. If that was indeed his calculation, he did not foresee the scale of the imperial response. Constantine sent his oldest surviving son and caesar Constantinus to campaign across the Danube. This imperial thrust, so we are told, drove many Goths (the sources speak improbably of 100,000) into the wilderness to die of hunger and cold. Constantinus demanded and received Gothic hostages, amongst them a son of the Gothic king Ariaric.[70] The defeat of the Goths was followed by a successful campaign against the Sarmatians, who had supposedly proved unfaithful to their agreements with the emperor.
Rome's Gothic Wars: From the Third Century to Alaric (Key Conflicts of Classical Antiquity) Page 9