TO INVADE ITALY WAS no simple task. Maxentius had the advantage of well-developed defenses, and Constantine’s force would be limited both by the need to defend the Rhine frontier while he was away and by considerations of logistics. To supply armies larger than 40,000 men seems to have been beyond the capacity of the ancient military art, and Constantine had before him the example of Galerius’ failure, which had begun with the collapse of the army’s supply lines. For the campaign to be successful, he would need to strike hard at northern Italy, compelling the enemy forces to give battle in the open, overwhelming them before they could withdraw behind strong defenses. Only if he was successful in this operation would he be able to march his army to Rome without calling on extensive reinforcements that would denude the Rhine frontier or make his own columns too big to supply. He would then have to capture one of the most impressively fortified cities in the world.1 No wonder he appears to have been spending a good deal of time in prayer.
There were three ways that an army could advance from Gaul into Italy, and to each there were advantages as well as disadvantages, as any student of the civil war of AD 69 would know. On January 1 of that year, Vitellius, the governor of what was then Lower Germany—so called even though in our reckoning it was the northernmost of the two Roman provinces on the Rhine because it was farther from the sources of the river—had been proclaimed emperor by his troops. By early March, Vitellius’ generals had managed two crossings of the Alps with a total of some 40,000 men, uniting on the plain of the Po valley near the city of Cremona. Here they defeated the armies of the rival emperor, Otho, who saw that he would be unlikely to do better by prolonging the combat and committed suicide. The victorious armies of the spring were defeated in the early autumn by forces emerging from the Balkans, fighting in the interests of Vespasian, who had been proclaimed emperor in Judea in early July.
The armies of Vitellius had used two of the main passages over the Alps; one crossed the Petit St. Bernard pass between Mont Blanc and the Graian Alps, and the other crossed the Maritime Alps. The southern route involved an easier passage of the mountains, but an army and its supply line on this route were open to attack from the sea, which is precisely what happened to Vitellius’ men. An army coming through the Petit St. Bernard, a steep if short passage for an army to negotiate, risked getting trapped before the walls of Eporedia, the modern city of Ivrea, which had been founded around 100 BC to control the pass. If one could count on incompetence or treason—a crucial factor in AD 69, when the unit garrisoning the area had declared for Vitellius—this might not be a risk. But AD 69 had been a time of considerable chaos: Otho seized the throne only on January 15, having arranged the murder of his predecessor Galba; Galba had taken the throne a few months earlier after the suicide of Nero.
In 312 the situation was different. Maxentius’ main forces were already in northern Italy, albeit concentrated around the imperial capitals at Milan and Aquileia, but still close enough to be able to resist anything but the swiftest and best-disguised advance from Gaul.2 Faced with a potential holdup at Eporedia as well as a rival who had at his disposal the major naval bases of the Mediterranean, Constantine chose a third route, this one across the Alps near Mt. Cénis. The first garrisoned city that he would hit was the modern Segusio. According to reports that formed the official tradition for later generations regarding the campaign, Segusio refused to surrender but fell to an immediate assault as Constantine’s men scaled the walls and set fire to the gates.3 The operation appears to have been well planned, and it created an immediate problem for Maxentius’ commanders: Turin was the next city in Constantine’s path.
Turin was a major city. Could it simply be abandoned? Could it be reinforced before Constantine arrived? Neither operation was plausible because the biggest formations of Maxentius’ northern armies were still around Milan, and the abandonment of a major city would have a serious psychological impact. The effects of the destruction of Segusio were no doubt already felt, as the citizens of Turin would have been aware that, in the event of a siege, their fates would be tied to that of the garrison. Constantine could have had no doubt about the stress he was causing.4
The dilemma facing the commander at Turin reflects Constantine’s own understanding that war, especially civil war, was a political as well as a military process: if significant units of Maxentius’ army were seen to be defeated or retreating before him, it could undermine the loyalty of others. The element of surprise was the one thing that Constantine might, with luck, be able to control since it would have been difficult for Maxentius’ commander, Rauricius Pompeianus, to know exactly where Constantine might be appearing in Italy. The approaches to both the pass at Mt. Cénis and the Petit St. Bernard began at Lyons. If Constantine could keep his intentions secret, he would have an advantage given that the enemies’ spies couldn’t move much faster than he could.
In the planning of this campaign, two immensely important aspects of Constantine’s character emerge—both the capacity to look into the mind of a potential opponent so as to understand the constraints under which the opponent operated, and a fundamental ability to command the enormous amount of detail necessary for launching a successful operation.
The earliest account of the battle outside Turin claims that the battle was won by a charge of Constantine’s heavily armored cavalry, which, massed in a wedge formation, overthrew the front of their enemies and turned their army in rout. Such cavalry had come into Roman service in the time of Aurelian, who first introduced cavalry units whose riders wore tall helmets, covering their bodies with chain mail riding heavily armored horses to supplement the existing heavy cavalry units whose lance-wielding men wore chain mail coats covering only their torsos and rode unarmored horses in battle. Such super-heavy cavalry had long been used by some tribes north of the Danube and in Persian armies, and they could be very effective against unformed infantry or more lightly armed cavalry units, or units whose flanks had been turned. They were not especially useful against formed infantry as their horses would not charge home against massed spearmen, and their effectiveness was limited in bad weather (the heavily burdened horses tended to bog down in mud) or on hot days when heat exhaustion would set in rapidly. When opposing armies both had such units they tended to cancel each other out. Indeed, on another source for the campaign—the arch erected at Rome to commemorate Constantine’s victory—heavily armored cavalry are notably absent from depictions of Constantine’s side (they do show up in Maxentius’ army, but as drowning men in the Tiber). Constantine’s heroes are more lightly armed horse and infantrymen, and rightly so. In a battle between two technologically equivalent armies—as would have been the battle of Turin—victory went to the side with the better soldiers (see figure 15.1). As these men moved into battle, wielding their spears and long swords, experience mattered. An enormous advantage was held by men who had stood their ground when a comrade had gone down with a Frankish axe in his skull, who knew that they could rely on their neighbors as they fought the brutal one-on-one battles to their front that would determine their fate. The longer a battle went on, as the wall of bodies between two units grew, as exhaustion threatened, the better the chances of the veteran. It was less likely that men would start looking to the rear—units always broke from the rear as people began to slip away rather than take their turn in the front rank—in a unit whose men had fought together, whose men were familiar with the dreadful sounds and odors of combat. The day at Turin went most likely to Constantine’s veteran infantry, men who had fought in the yearly battles with the Franks and Alemanni, and took from those encounters the experience that gave them a decided advantage against the men of Maxentius.5 In the end Maxentius’ men broke; Turin surrendered and was spared a sack—something perhaps easier to arrange since the army had been fed a city a few days earlier.
FIGURE 15.1
The army of Constantine. Note the stress here on Constantine’s infantry and the winged Victory that accompanies them in the bottom picture, showing the capture of Verona, while the top picture shows the battle of the Milvian bridge where, interestingly, the only mailed cavalry are on Maxentius side and they are being driven into the river by Constantine’s more lightly armed horsemen. Source: Courtesy of the author.
The battle of Turin was the critical turning point in the Italian campaign. The surviving forces in the north pulled back in the direction of Verona, leaving open the road to Milan, which followed Turin in surrendering without a fight. To have so easily won control of an important imperial capital was a victory of symbolic significance and led other cities in the area to pledge Constantine their loyalty. Staying a few days at Milan, which enabled his soldiers to rest while he stabilized his control, Constantine then set out in pursuit of Pompeianus and the surviving Maxentian forces.6 Pompeianus, who seems to have just suffered a preliminary defeat at Brixia (Brescia), first chose to defend Verona; but soon, possibly fearing treason, he tried to break up the siege line with a sally in force—duly repulsed by Constantine—even though Pompeianus made his escape in the course of the battle with a view to commanding the reinforcements coming to raise the siege.
The final battle of the northern campaign would thus be fought outside Verona, where Pompeianus failed to break the siege and his army fled, much of it subsequently going over to Constantine. Constantine then occupied Aquileia on the northwest coast of the Adriatic, the site of the palace that allegedly had his youthful image on display. The later version of the last battle has Constantine doing his best imitation of Galerius during the Persian war, setting off on a scouting mission with no more than a couple of comrades before the two sides engaged. The story of Galerius’ scout may be no more based in fact than this one, but both served to emphasize the role of the emperor in every phase of a military operation. Insofar as the anecdote about Galerius may have been well established, the invention of this story illustrates the constant battle that Constantine felt he had to wage against the memory of the old regime.7
Constantine’s victories in the Po valley made it impossible for Maxentius to rely on the defenses of Rome, and with a substantial portion of his original army now destroyed it is unlikely that he could muster a force much greater (if any greater at all) than that of Constantine. Treason may well have been in the air—many of Maxentius’ associates would rapidly find places in the highest echelons of Constantine’s regime, which suggests that negotiations may have been opened between their houses and his camp as he moved south. Lactantius says there were demonstrations in the circus at which the crowd proclaimed Constantine’s invincibility, while the panegyrist of 313 says that the divine spirit and eternal majesty of the city robbed Maxentius of his senses (these may be two ways of saying the same thing, since Lactantius is ignorant of a very great deal that happened during the campaign).8 As Constantine approached Rome, Maxentius appears to have ordered the Sibylline books to be consulted—these were rather remote descendants of the collection that had guided important aspects of Roman religious practice for many centuries.
On October 28, Maxentius reappointed Anullinus as prefect of the city (evidently as a good luck gesture), the position he had held on the day Maxentius seized power. He then rode to war, though probably with little confidence as he stowed away the symbols of his imperial power in wooden boxes under a shrine near the Palatine. There they would remain until December 2006 when Italian archaeologists uncovered them. They contain, wrapped in linen and silk (probably), three lances, four javelins (Maxentius’ hunting gear?), a base into which standards could be placed, three glass and chalcedony spheres, and a scepter. When he hid these objects, Maxentius was no doubt aware that there was a good chance he was not coming back.
Although the battle of the Milvian Bridge is often seen nowadays as the culmination of Constantine’s career, the moment at which he became a Christian as the result of having seen the vision of a cross in the sky inscribed with the words “in this sign, conquer,” and as a victory of faith over tyranny, none of these perspectives has much to do with what actually happened—and not even Eusebius claims that the vision was immediately before the battle, where it ends up in very many more recent depictions of the conflict. Constantine had begun the spiritual journey that would result in his conversion well in advance of the battle—before crossing the Alps if our reading of the obscure reference to Divine Mind in the panegyric delivered in 311 is any indication. Maxentius himself was hardly a persecutor, and the battle does not seem to have been particularly hard fought. Constantine arrived outside Rome riding a wave of success; Maxentius commanded an army whose men knew that they were probably overmatched. It could not have helped morale any that he drew them up with the river to their back as if making a statement that they could fight or die—not really an effective line to take with men who would have been well aware that Constantine was not in the habit of massacring his prisoners.
FIGURE 15.2
Constantine’s victory. Despite the poor state of preservation it is possible to pick out Constantine, who is the second figure on the left, and the shape of a winged figure leading him onward (this would be a Victory), while the figure wearing the large crown is the city goddess Roma. Source: Courtesy of the author.
When the armies were drawn up, Constantine’s men appear to have displayed a new symbol that combined the Greek letter Chi (pronounced with a strong “ch”) with the letter rho (our “r”); this could be interpreted either as a reference to the name of Christ or to the word chrestos (“good luck”). Lactantius says that this was because Constantine had announced that he had a dream that had instructed him to place this symbol of the “Highest God” on their shields. In so doing he looked to a long tradition in which Roman generals had revealed such visions to their men on the day of battle. Not even Lactantius suggests that this was a specifically Christian sign on the day, even though it would later figure on the Labarum, Constantine’s personal standard, and become a symbol of imperial Christianity. On October 28 it was a device to raise the morale of the men before they attacked.9
Attack they did, and, as at Turin, his infantry appears to have won the day. His cavalry chased the remnants of Maxentius’ forces into and across the river. Maxentius himself was evidently seen to fall from the bridge into the river, or that is what the panegyrist of 313 would have us believe: “the Tiber devoured that man, sucked into a whirlpool, as he was vainly trying to escape with his horse and impressive armor up the far bank.”10 On the arch that was dedicated at Rome in 315, the left-hand side of the panel depicting the battle shows Constantine on the bank looking over at Maxentius who is falling from the bridge into the river as the goddess Victory, standing beside the goddess Roma, beckons to him from the far bank—two of three female figures who play an immensely important role in the original story telling how Constantine found the confidence to launch the invasion of Italy.