Authors: Stephen Dando-Collins
In
AD
274, the same year that Aurelian surrendered the Roman province of Dacia to the barbarians and withdrew all Roman troops south of the Danube, he celebrated a Triumph through the streets of Rome for his victory over the Palmyrans and for restoring Roman control to the eastern provinces. It had been a long time since Rome had anything to celebrate. The hundreds of thousands of Romans lining the streets saw Zenobia and two of her sons on display in the triumphal procession. According to legend, Zenobia was led in golden chains. Just to prove she was no ordinary prisoner, she was kept at the famous villa of the emperor Hadrian at Tivoli, just outside Rome. Zenobia later married a Roman senator, and lived out the remainder of her life in Italy.
AD
305–312
LXVI. CONSTANTINE FIGHTS FOR THE THRONE
Victory under a new standard
The Roman Empire of the fourth century was rent from within by civil wars and eroded from without by the inroads of numerous foreign invaders. Peace, security, stability, these were all things of which fourth-century Romans could only dream. Yet the century started on a promising note. The emperor Diocletian and his co-emperor Maximian had vowed that they would rule for twenty years and then retire, handing over power to others. Uniquely, in
AD
305 the two emperors abdicated, with Diocletian famously secluding himself in his vast palace at Salonae in Dalmatia, today’s Split in Croatia.
The two emperors had prepared for an orderly transition of power by appointing a pair of co-emperors for both the East and the West, also appointing a Caesar under each co-emperor. While sharing power around eight men may have seemed to Diocletian and Maximian a sure way to prevent a single despot from gaining power, it was in fact a formula for bitter internal rivalry. For, in leaving power in the hands of eight men, the pair created a recipe for in-fighting that would dominate Roman affairs for nineteen years and cost the lives of thousands of Roman soldiers in a series of costly civil wars.
It was Flavius Valerius Constantinus, or Constantine the Great as we know him, who would eventually emerge from the chaos as the sole victor. As Constantine I, he would go into the history books
as the first Christian emperor, an excellent general and a man of intelligence, and the emperor who gave the city of Constantinople its name. He was all those things. But he was also cunning, ruthless, brutal, vindictive, paranoid and obsessed with glory. Diocletian had separated military and civil commands in the provinces. But it was the subsequent changes that Constantine wrought on the Roman army, from the organization and distribution of units to the structure of the officer corps, combined with the losses suffered in wars internal and external, that weakened the army to such an extent that within 100 years the Roman military would prove incapable of preventing the barbarians from sacking Rome. The army would also prove incapable of preventing the Roman Empire in the west from disappearing altogether within little more than 150 years.
Classical authors put Constantine’s age when he died, in
AD
337, at between 62 and 66. [Eus.,
EH
,
LIII
] Born in Upper Moesia, Constantine was the son of Constantius Chlorus, great-nephew of the emperor Claudius II, one of Rome’s crowd of emperors during the last half of the third century. Constantine’s father pursued a military career, starting out with the imperial bodyguard and rising to become governor of Dalmatia and then Caesar for the west. Constantine himself was educated as part of the court of the emperor Diocletian at his capital of Nicomedia in Asia, and served as a tribune in the army which Diocletian took on an expedition to Egypt in
AD
296.
Constantine fought the Sarmatians under the deputy emperor Galerius, the son of Diocletian, and is likely to have also served under him in his wars with the Persians. According to an anonymous contemporary biographer, “When Constantine, then a young man, was serving in the cavalry against the Sarmatians, he seized by the hair
and carried off a ferocious barbarian, and threw him at the feet of the emperor Galerius.” Later in the same campaign against the Sarmatians, Constantine “slew many and won the victory for Galerius.” [Vale., 2, 3]
On the abdication of Diocletian and Maximian, young Constantine was not named as a Caesar to his father, the new co-emperor of the west, as he would have expected. When Constantius sought permission from the new Eastern emperor Galerius for his son to join him on an expedition to Britain to counter troublesome Picts in the north, at first Galerius was reluctant to release young Constantine, but he eventually agreed. Constantine left the palace at Nicomedia that same evening in a carriage of the Cursus Publicus Velox and hurried west, laming the horses at each Cursus Publicus station he passed through so that no message could overtake him rescinding the emperor’s permission. [Ibid., 2, 4]
At Bononia on the coast of Gaul, Constantine joined his father, and from there the pair crossed the English Channel by ship, then hurried north. In the spring of
AD
306, father and son led Roman forces in a campaign north of Hadrian’s Wall, and won “a victory over the Picts.” [Ibid.] But in the middle of the summer Constantius fell ill, and had to return to the provincial capital, Eburacum. There, in July, with all his children around him and having anointed Constantine as his successor, Constantius died. On July 24, the Roman troops in Britain hailed Constantine as the new emperor in the west. As soon as news of the death of Constantius reached Rome, the Praetorian Guard hailed Maxentius, son of the abdicated emperor Maximian, as their choice of Emperor of the West. This creation of a rival emperor to Constantine sparked a series of civil wars that would last for years.
From the East, the emperor Galerius reluctantly granted Constantine the title of Caesar, but would not recognize him as his equal as Emperor of the West. For the moment, Constantine accepted the role of deputy emperor, and to cement his claim to ultimate power, married the daughter of abdicated emperor Maximian and sister of Maxentius.
Galerius, meanwhile, would not accept Maxentius’ claim to be Emperor of the West, and sent his deputy emperor Severus marching to Rome with an army to unseat him. Severus was “low both in character and in
origin” and “given to drink.” [Ibid., 4, 9] His troops did not respect him, and when Severus reached Italy in
AD
307 he was deserted by his army and was forced to flee to Ravenna. Maxentius’ father Maximian now came out of retirement at his son’s behest and went to Severus at Ravenna. Through deception, Maximian made Severus a prisoner and took him to Rome, after which Severus was kept at an imperial villa at Tres Tabernae, 30 miles (48 kilometers) south of Rome. [Ibid., 3, 11]
Determined to punish Maxentius, Galerius himself then marched an army from the East to Rome. Camping at Interamna, today’s Terni in southern Umbria, just to the north of the eternal city, Galerius sent envoys to Maxentius in Rome to convince him to submit to his authority. Not only did Maxentius send the envoys packing, he offered bribes to Galerius’ troops, and some of them even defected as a result. Unsettled by this, Galerius withdrew from Italy, but, “in order to supply his men with whatever booty he could” and so placate their greedy demands, he gave them permission to sack the Italian towns they passed through on the Flaminian Way north. [Ibid., 3, 7] As Galerius and his looting army marched away, Maxentius ordered the execution of his prisoner, the deputy emperor Severus, humiliatingly “in the midst of his own troops, as it were.” [Eus.,
EH
,
XXVII
]
Galerius’ health was in decline; he would be dead within four years. He now retreated to Illyricum, and let Maxentius and Constantine fight it out to see who would become sole emperor of the Western Empire. According to Eusebius, who spoke to Constantine on the subject, Constantine resolved to overthrow Maxentius after “those who had attempted it,” Severus and Galerius, “had experienced a disastrous termination of their enterprise.” [Ibid.,
XXVI
]
On the other hand, historian Zosimus wrote that it was Maxentius who made the first move toward war with Constantine. To begin with, Maxentius supposedly fell out with his father Maximian, who sought refuge with Constantine in Gaul. [Zos., 2, 14] From there, Constantine efficiently dealt with a series of raids by the Bructeri and the Franks, “barbarians who dwelled on the banks of the Rhine,” and made allies of the Alemanni. [Eus.,
EH
,
XXV
] Once he had Constantine’s confidence, the elderly Maximian then twice tried to betray him, the second time paying for his treachery with his life. Now, said Zosimus, Maxentius used the pretext of avenging his dead father to prepare for war with Constantine. [Zos., 2, 14]
Throughout his career, Constantine had a habit of moving much more rapidly than his opponents expected. In the spring of
AD
312, before Maxentius could mobilize
his forces for an expedition to Gaul, Constantine crossed the Alps into Italy with an army made up of men from the garrisons of Britain, Gaul and the Rhine. The identity of individual units in his force is not known, but it was particularly strong in mounted troops—Constantine had much personal experience with the cavalry arm.
The “obscure and imperfect narrative” of Zosimus, in the words of Gibbon, put the number of men in Constantine’s force at this time at an excessive 90,000 foot and 8,000 horse, and gave Maxentius an amazing 170,000 foot and 18,000 horse. [Gibb.,
XVIII
, n. 22] This total, of close to 300,000 men, would have been by far the largest number of Roman troops in Italy at any time during the imperial era, a number that, at that time, is simply not credible. A more reliable ancient source put Constantine’s force at less than 40,000 men. [Eus.,
HE
,
Prole
., n. 3014] From later events, 8,000 cavalry would seem a realistic figure, while his infantry probably numbered 30,000. The same source gave Maxentius 100,000 men. [Ibid.] These lesser numbers are supported by the fact that within a few years Constantine would be leading an army of just 20,000 men into battle, with his opponent the then Eastern Emperor, Valerius Licinius, commanding 35,000. [Vale., 5, 27]
Meanwhile, from where did Maxentius amass so many troops at Rome? Even 100,000 soldiers was a huge army by the standards of the Late Empire. A number of cohorts of the Praetorian Guard were permanently stationed in Rome, but how many there were at this time is not known. Septimius Severus increased the Praetorian Guard to 15,000 men, but some Praetorians may have been serving with the Eastern Emperor Galerius and his successor Licinius. Likewise the household cavalry, the Imperial Singularian Horse, numbered 2,000 men at this time, but how many, if any, of those troopers were with Galerius is unknown.
The 2nd Parthica Legion, stationed at Alba Longa just south of Rome, was without doubt in Maxentius’ army. In addition, Maxentius had incorporated Severus’ eastern troops into his forces after they had changed sides on reaching Italy. According to Zosimus, Maxentius’ army also included troops from Carthage, Sicily and Italy. [Zos., 2, 15] These men may have been freshly levied by Maxentius, in which case they could barely have been trained by the time that Constantine marched into Italy. The troops from Carthage, in addition to Moor and Numidian cavalry, may have also included the 3rd Augusta Legion; the only legion then based in North Africa, this unit would not be located in North Africa when the Notitia Dignitatum was written later that century. [Not. Dig.]
Once Constantine’s army crossed the Crottian Alps from southern Gaul it stormed its way into the pro-Maxentius town of Sigusium (modern Susa in Piedmont), in northern Italy. Constantine’s troops set fire to the town after they crashed through its gates, but Constantine had them extinguish the flames and save the town, and treated his prisoners well—so that word of his clemency would go on ahead of him and incline other Italians toward his cause and against that of Maxentius.
As Constantine proceeded southeast, 40 miles (64 kilometers) from Susa a large opposing cavalry force arrived from its base at Mediolanum, today’s Milan, and formed up in his path on the plain near Augusta Taurinorum, modern-day Turin. The mainstay of Maxentius’ cavalry force were units of heavily armed cataphracts in chain mail, with their horses also clad in mail, and the even more heavily armored cavalry, called the Clibarnii, who wore suits of segmented armor that presaged the armored knights of the Middle Ages. This style of heavy cavalry had been “borrowed from the nations of the East” by the Romans. [Gibb.,
XIV
] Maxentius himself was still at Rome, 450 miles (725 kilometers) away, so that the force that now opposed Constantine was commanded by Maxentius’ subordinates.
The Maxentian cavalrymen, who had formed up in a massive wedge, point forward, “flattered themselves that they should easily break and trample down the army of Constantine.” [Ibid.] Constantine sent his mixed force of cavalry and infantry against the opposition cavalry using complex maneuvers which “divided and baffled” the Maxentians. Soon the Maxentian troopers were fleeing in disarray to Turin, with Constantine’s army in hot pursuit. The city of Turin closed its gates and refused to admit the retreating Maxentian cavalry, and outside the city walls Constantine’s men isolated and butchered their mounted opponents. “Very few escaped.” [Ibid.]
Following this comprehensive victory, Constantine led his army on to Milan, which, like Turin before it, welcomed him. Briefly, he occupied the city’s imperial palace, as envoys arrived from cities throughout northern Italy with vows of allegiance. One city that did not submit to him was Verona. Under the command of Ruricius Pompeianus, an experienced general, the city closed its gates and prepared to defy Constantine. A cavalry force ordered west by Pompeianus to intercept Constantine’s army was sent reeling in retreat after an engagement near Brescia, and Constantine arrived outside Verona and surrounded the city. A sally outside the walls by Pompeianus’ troops was easily repelled, and Constantine prepared for a protracted siege of the city.