Eharding on the fall of the Roman Empire, Part IV/XII: the triumphs of Diocletian and Constantine
Diocletian and Maximian reorganized the tax system in order to reverse the negative effects of the later third century inflation on revenue. Starting in 293, they attempted a coinage reform of the same manner Aurelian had with his aurelianianus -substituting old, heavily debased coinage, with new, slightly higher value coinage, the nominal appreciation being higher than the actual appreciation. The reform was intended to be highly broad based, even ending Egypt’s traditional status as a separate currency zone based on the drachma. Since coinage was no longer minted solely from Rome, mint marks were added to the coins. During the same reform, Diocletian first restarted the minting of real silver coins for the first time since the days of Septimius Severus, though, due to Gresham’s Law, this minting would remain very small-scale and intermittent until after 355. Precious metal coinage was still a store of large value, rather than an actually used medium of exchange. The centerpiece of the reform and the most widely minted medium of exchange during his reign were 4% silver billon nummi, which, despite Diocletian’s refusal to debase them throughout his reign and their threefold increase in weight and two and a half-fold increase in silver content over Aurelian’s billon coins, were, due to the unacceptably large nominal appreciation, not entirely trusted by the populace (thus resulting and Diocletian’s infamous Price Edict). For smaller change, a radiate fractal coin was issued. These, however, were not used as a unit of account -that was a ghost currency, the denarius communis. In January 300, the emperors, responding to rising prices in nummi, increased the nummus‘s unit of account value by fiat from 5 to 12.5 dc. On September 1, 301, the emperors doubled the unit of account value of the nummus by fiat from 12.5 to 25 dc, crippling creditors, who the emperors mandated had to accept half the coins for the same pre-September 1 debt. The two nominal revaluations did not, however, result in the expected rapid fall in prices, as the currency stock had not contracted. As a result, Diocletian issued his extremely wide-ranging Edict on Maximum Prices three months later while increasing the pay of numerous officials in an attempt to simultaneously please both officials and soldiers and conserve government expenditure. Despite violations of the price edict being punishable by death, it eventually stopped being enforced after sellers refused to obey. Heirs of Maximinus Thrax, militarily effective as they might be, don’t make for the best designers of economic policy.
Then much blood was shed for the veriest trifles; men were afraid to expose anything to sale, and the scarcity became more excessive and grievous than ever, until, in the end, the ordinance, after having proved destructive to multitudes, was from mere necessity abrogated. To this there were added a certain endless passion for building, and on that account, endless exactions from the provinces for furnishing wages to labourers and artificers, and supplying carriages and whatever else was requisite to the works which he projected. Here public halls, there a circus, here a mint, and there a workhouse for making implements of war; in one place a habitation for his empress, and in another for his daughter. Presently great part of the city was quitted, and all men removed with their wives and children, as from a town taken by enemies; and when those buildings were completed, to the destruction of whole provinces, he said, “They are not right, let them be done on another plan.” Then they were to be pulled down, or altered, to undergo perhaps a future demolition. By such folly was he continually endeavouring to equal Nicomedia with the city Rome in magnificence.
–Lactantius, Of the Manner in Which the Persecutors Died
Diocletian’s intent had been to strengthen both defensive and offensive military capability, defang the military from going outside its purview, restore an acceptably non-inflationary currency, and restore a reasonable process of succession. All of these achievements would fall apart before the century following Diocletian’s resignation was over. The only one of his achievements that survived beyond that century was the pacification of Egypt, which would only end with the rebellion of Heraclius in the early seventh century. The monetary system, at least, would be stabilized for some six hundred years on lines somewhat different than Diocletian had originally planned on.
For several decades, however, the army reforms of Diocletian were successful in restoring its strength against the Persians and barbarians. The army of Diocletian was said by John the Lydian to have been 389,704 men and its seaborne forces (the Roman Empire did not fight naval battles; it did transport troops by sea and use patrol ships) 45,562 men, and this figure appears (at least, according to all written sources) to have been greatly expanded during his reign due to the institution of two emperors encouraging redundancy. Soldiers became conscripted in the same way taxes were collected -through demanding a quota from landowners and cities’ lands. The number of provinces was increased, to both ease the burden on commanders and to make usurpations more difficult. The number of garrison forces was increased, resulting in the construction of massive new walls around cities in Gaul and northern Hispania and the expansion of a thousand-year old tradition of fortification in the the deserts of southern Palestine begun by the Omrides and expanded by the Judahites and Assyrians. The fortunes of Sirmium on the Sarmatian frontier and Trier in the Rhineland dramatically improved.
As the Empire was divided, however, so were legions, into units similar in size to High Imperial vexillations. An excellent example of this is the old fifteen hectare Legio VI Ferrata base next to Maximianopolis/Kefar Othnay in the Jezreel Valley, comparable in size to the 16.7 hectare camp at Featherwood East, the 16.1 hectare camp at Bellshiel, and 15.8 hectare camp at Featherwood West, all North of Hadrian’s Wall, as well as the 15.3 hectare Legio III Cyrenaica camp at Bostra in southern Syria. Under Diocletian, the Legio VI Ferrata base next to Maximianopolis was decommissioned and the legion moved to a 4.6 hectare fort at Augustopolis on the Arabian frontier (this base is currently being increasingly damaged by modern construction, as is much else in Jordan), almost exactly the same in size as the 4.5 hectare Legio IV Martia base at Betthoro in Moab and comparable to the 3 hectare Trajanic fort at Humayma designed for a vexillation of a thousand men. The 3.7-fold reduction in legionary base size strongly suggests the Diocletianic legion had been reduced to 1500 men (5500 principate legion divided by 3.7). This is without a doubt a maximum figure, very likely reduced still further by later emperors. Vexillations became units of five to six hundred men, about the equivalent of a High Imperial cohort. The 2.1 hectare fort at Mefa (Umm er-Rasas South), comparable to the 1.88 hectare Severan fort at Umm el-Quttein designed for one cohort of the Augusta Thracum Equitata (now destroyed by modern construction, though outlines are still visible; see Kennedy, The Roman Army in Jordan, p. 82) seems sufficient to hold one Diocletianic infantry vexillation. “Cohorts”, “maniples”, and “centuries” also shrank, and there is no reason whatsoever to believe the standard of a cohort being a tenth of a legion was ever abandoned. Diocletianic Betthoro (The Roman Army in Jordan, p. 155) contains barracks arranged in twenty blocks- four groups of four blocks of sixteen rooms, plus three additional blocks of twelve rooms and one (two?) additional block of six, making altogether about three hundred residential rooms. From the papyrological evidence, it appears the cohort was a unit of some 160 men, and that the ala had shrunk from a unit of about 550 men to one of about 120 (on this, see Duncan-Jones, Structure and Scale in the Roman Economy, p. 111). The 160 men figure is quite concordant with 32 Betthorus rooms assuming one room housed five men. The smallest Diocletianic forts in Jordan (Qasr el-Hallabat, Yotvata, Qasr eth-Thuraiya) are all about .14 hectares in size. The one Roman fort in Jordan where a cohort is known with absolute certainty to have been stationed both under Diocletian and the first Theodosius was also just .14 hectares in size (actually less; the interior of the site is only some 1000 square meters). This is just enough space to hold thirty-two Diocletianic barrack rooms -but no more (the combined area of the two sixteen-room barrack blocks on the Eastern side of the Diocletianic fort at Dajaniyah, including the corridor separating them, is 1200 square meters). It thus appears that the Diocletianic legion was divided into ten cohorts, eight of these being 160 men, the other two being 120, or “roughly the size of an old maniple“.
Despite this shift of funds toward the military, the grain dole for the major Roman cities was not reduced, and was possibly even expanded. The liberty of landless tenants to leave the land they resided on was restricted, thus providing a great stimulus to agriculture both in the Roman West and East. The reforms in the short term worked -the Carausian usurpation, two Egyptian usurpations, the Moors threatening the Roman Southwest, and, most importantly, the Persians threatening the Roman Far East were all crushed in a highly decisive fashion. A great column was set up under Diocletian in Alexandria, the largest such column outside the imperial cities of Europe, which stands even unto this day, commemorating the victory over the usurpation of Domitius Domitianus. The more one learns about the events of the coming centuries, the more impressive Diocletian’s accomplishments look.
In 293, the same year as their coinage reform, Diocletian and Maximian appointed their most capable generals, Galerius, who would go on to crush the Persians and build one of the last great monumental complexes of the classical empire, the fortress of Felix Romuliana in Serbia, and Constantius, who would go on to reconquer Britain and northern Gaul from Carausius and Allectus, to serve as their successors. Both men were, naturally, born within the borders of present-day Serbia. Both would die of natural causes quite early -Constantius on 25 July 306; Galerius on 5 May 311. The result of the premature death of the first was the breakdown of Diocletian’s system and the triumph of new attempts at hereditary succession with the ascent of his son, Constantine.
SOURCES: Agathias, Zosimus, Lactantius, Aurelius Victor, the Twelve Latin Panegyrics, the Verona List
Overall, I find it hard to think of the eras of Diocletian in the 280s-290s and the Valentinians in the 360s to be anything other than restorations of imperial strength, while I find it hard to think of the war-torn eras of Constantine I, Constantius II, Julian, and Theodosius I to be anything other than presaging the fall of the Western Empire that began in 406-8. Without any precedent, Diocletian and Maximian resigned in favor of their designated successors on May 1, 305 (something a good many government officials who have stayed on in the same office for over a fifth of a century don’t do even today). The arrangement they had created quickly began to fall apart with the usurpation of Constantine, born in Nish, Serbia, on the event of his father’s death in York, Britain. The resignation of Diocletian and the ascent of Constantine constitute a convenient chronological midpoint between the triumph of Octavius and the Arabs’ triumph over Heraclius, and, if one wishes, a convenient boundary marker between the classical and postclassical empires. If Diocletian were the Julius Caesar of the postclassical empire, Constantine was its Octavius. The Romans, thus, quickly fell into their equivalent of the Chinese War of the Eight Princes, the Roman equivalents being Constantine (won the war), Valerius Severus (deposed with Maxentius’s capture of Ravenna in April 307), Maxentius (usurped power in Rome with the support of the Praetorian Guard on October 28, 306; drowned at the Battle of the Milvian Bridge six years later), Maximian (aligned with Constantine; forced to commit suicide by Constantine after a failed rebellion against him in Arles in 310), Domitius Alexander (seized power in Tunisia in 308, allied with Constantine against Maxentius, defeated by Maxentius), Galerius (failed to conquer Italy from Maxentius; died of bowel cancer in 311), Maximinus Daza (failed to conquer Balkans from Licinius in April 313, died in Tarsus in July 313), and Licinius (won against Maximinus Daza in the Balkans in 313; took the rest of the Roman East with Maximinus Daza’s death). By the end of 308, the Empire possessed two “official” emperors (Galerius in the East and Licinius in Pannonia/”the West”), two partially recognized usurpers (Constantine in Trier and Maximinus Daza in Antioch), and two unrecognized usurpers (Maxentius, the son of the late Western emperor Maximian, in the City of Rome and Domitius Alexander, not recognized by Maxentius, in Carthage). Imperial debasement of the nummus, unthought of by Diocletian, began two years after his resignation and became extremely severe and continuous for the next several decades. Roman price inflation between 301 and 359/67 averaged 16%-18% per year (The Cambridge Companion to the Age of Constantine, p. 236).
Constantine, thus, became the primary innovator of the Roman army of the fourth century, separating units of the field army (auxilia palatina and comitatenses) from those of the garrison army (limitanei). Soon after his capture of the City of Rome at the Battle of the Milvian Bridge, he disbanded the Praetorian Guard and demolished their barracks on the border of the city, and soon after founded the scholae to replace them as imperial guards -the City of Rome, where the Praetorian Guard was based, had long ceased to be a permanent imperial residence. After he reunified the Empire, the term “vexillation” stopped being used to refer to infantry units altogether, becoming instead used for units of 350 (the number is based on Ammianus Marcellinus) to five or six hundred (upper bound) horsemen. During his time (apparently during 310-312), the Roman military peaked in size (according to a source apparently used by Agathias and Zosimus; on this, see the discussion in Treadgold, Byzantium and its Army, Chapter 2) at an astonishing 645,000 men -more than 1% of the Empire’s total population, and as much as 10% of the Empire’s eligible population -a figure substantiated by the panegyrics. The firmest possible proof of this is not textual sources, however, but the evidence of archaeology for the construction of new town walls combined with the occupation of new (or re-occupation of old) forts and, still more conclusively, that the Persians stayed rather quiet and that the barbarians, so far as anyone can tell, were no great threat. The civil wars of Magnentius in the 350s, Maximus in the 380s, and Eugenius in the 390s would be extremely different in their consequences.
SOURCES: Eusebius, Zosimus, Hesychius, John the Lydian, Socrates
However, despite its loss of status as the imperial residence, the City of Rome remained the largest city in the Mediterranean, home to some three hundred thousand people, though definitely down from the half million or so during the Early Empire. Only Alexandria, a city even further from any major frontier, could compare in size. In monuments, of course, Rome was extremely overbuilt, leaving no further room for improvement. It only made sense, thus, for a new great city to be established for the East -not Antioch, too far from the Goths, or Sirmium, too isolated from Persia, but somewhere in between these two extremes. In order to restore some of the glories of the massive public building and imperial ceremonies of the Principate while preserving the frontier-focused structure of the Dominate, Byzantium was selected in 324, some three and a half centuries after the triumph of Octavius and some three and a half centuries prior to Constantine IV’s victories over the Arabs, by Constantine after his defeat of the Eastern emperor Licinius, thus reunifying the Roman Empire for the first time in 38 years, to serve as a second Rome for the Empire. The first Rome, formerly the primary headquarters of Maxentius, the last pagan emperor to rule from the City of Rome, was in the middle of the Western Empire; perhaps as far as one could get from the frontier armies -perhaps practical as a center of government in the days of Antoninus Pius or for the figurehead emperors of the fifth century, but not in the fourth century. By the time of Constantine’s usurpation, the emperor was no longer a justice –that’s what the bureaucracy was for– he was a general. The second Rome, conversely, was situated at one of two northern maritime gateways out of the Empire, on the border between the European and Asian continents, and directly between the Empire’s two most important frontiers -the Danube frontier with the Goths and Sarmatians, where Constantine would spend most of his remaining years, and the Syro-Anatolian frontier with the Persians, which would only become active again in Constantine’s last year. No other city could be better positioned to discourage the Empire’s enemies. It is for very similar reasons Diocletian had made his primary imperial residence in nearby Nikomedia. Imperial construction on the expanded city started in 326, one thousand years prior to the fall of Prusa to the Turks, and it was ready for use in 330. The area within the city walls of Constantinople would be 1700-1800 acres, just over half the area within the City of Rome’s Aurelian walls. It is no coincidence that the last major surviving new secular monuments of the City of Rome -the Basilica of Maxentius, the Arch of Constantine (largely built from remains of High Imperial monuments), the Colossus of Constantine (recarved from a statue of a bearded High Emperor, probably Hadrian), and the Mausoleum of Helena- were completed under Constantine. Like the first Rome, the second Rome would import much and, much unlike Alexandria and Carthage, would produce little for export except coins.