Forces Engaged: I apologize for doing this twice in a row, but we've gotta start from a different place here; the fact is that we just don't know much about the actual battle of Milvian Bridge, and the "things we don't know" includes even the bulk numbers of troops.
I'll get to this when we talk about Sources, but none of the extant accounts of the battle provide anything like an accurate number of combatants. The numbers we do have are, frankly, speculative. The forces loyal to Flavius Valerius Constantinus (afterwards Emperor Constantine I) are given as something between 90,000 and 100,000, while the forces loyal to Marcus Aurelius Valerius Maxentius (at the time styling himself Emperor Maxentius) is accorded a higher total ranging from something around 100,000 to Zosimus' report of 188,000.
The sources also state that these numbers could represent the TOTAL number of troops in the contenders' respective forces. Constantine is reported as having left three-quarters of his army along the Rhine frontier, while Maxentius was also engaged in a conflict with another claimant based in North Africa AND had already lost several north Italian cities and their garrisons.
So the actual forces engaged north of the River Tiber in October 312 seem likely to have been smaller than the reported numbers. The logistical constraints of 4th Century transport and comestible storage also argue for smaller numbers. The command-and-control technology of 312 would have tended to make an army of 100,000 almost uncontrollable; a smaller force (of, say, 20,000 to 40,000) would have been much easier to fight as well as to move and supply.
The accounts all suggest that Maxentius had the larger of the two forces at Milvian Bridge; the proximity of the logistical and administrative base in Rome, and the earlier campaign fought down through north Italy by the Constantinian forces, all suggest that the Maxentian force would have been larger than their enemies.
My guess is that the Constantinian force would have been roughly 30-40,000 while the Maxentian force might well have been twice that size, something like 50-80,000, but that's really all it is, a guess. We just don't know and probably never will.
The armies themselves were practically identical; a core of legionary infantry supported by auxiliary cavalry, light infantry, and projectile infantry (largely archers).
The 3rd and early 4th Centuries were times of great change and experimentation in the Roman armies. The "classical" imperial legion of 6,000 had been dominated by heavy close-combat infantry - the iconic legionary from his hobnail caligae sandals to his beavertail helmet, lorica segmentata armor, big cylindrical shield and stabbing sword. By the time of Milvian Bridge this had changed considerably.
Perhaps the most significant change was the fragmentation of the big legions. By 300AD the standard formation was a much smaller element. These had been originally termed "detachments" (vexillatio) but by the time of Milvian Bridge these were stand-alone units of 500 to 1,000.
The other major change was the inclusion of non-Romanized troops. The Wiki entry for the late Roman army notes that:
"From the 3rd century are the first records of a small number of regular units bearing the names of barbarian tribes (as opposed to peregrini tribal names). These were foederati (allied troops under a military obligation to Rome) converted into regular units, a trend that was to accelerate in the 4th century. The ala I Sarmatarum, based in Britain, was probably composed of some of the 5,500 captured Sarmatian horsemen sent to garrison Hadrian's Wall by emperor Marcus Aurelius in 175 There is no evidence of irregular barbarian units becoming part of the regular Principate army until the 3rd century."The Maxentian army is said to have contained more of these "barbarian" units, although this could well be Constantinian propaganda to make the loser seem less "Roman" than the winner.
The late Roman trooper also looked very different from his "classical" counterpart, from his clothing to his weapons.
Long-sleeved single-piece tunics (basically a short dress), trousers (bracae), socks and boots replaced the short-sleeved tunic and caligae that were the underarmor wear of the classical infantryman. A chain mail body armor - known as the lorica hamata - replaced the classical laminated-strip steel lorica segmentata which, while better protection was complex, difficult to produce and maintain, and had proved very uncomfortable in action (modern reenactors have found that the segmentata tends to catch skin between the bands and - since it is relatively stiff and doesn't conform to the torso - chafes horrifically within minutes).
The big cylindrical scutum had given way to the lighter, flat, round or oval clipeus and the gladius, the short stabbing sword had been phased out in favor of the spatha, a longer (about twice the gladius' length) weapon that had been a cavalry sword, but primarily the heavy hasta spear.
This, in turn, implies that the legionary formations of the 3rd and 4th Centuries had opened up, with fighting taking place at longer distances than in the earlier legionary infantry, which needed to get within embracing distance of an enemy to use the gladius.
The continued presence of short-range missile weapons, including throwing spears or javelins verrutum or lanceae, a heavy pilum called a spiculum, and unique lead-weighted throwing darts called plumbatae suggest that the early Roman tactic of preceding the clash of heavy infantry with a volley or two of missiles persisted into the time of Milvian Bridge.
The cavalry had proliferated, and now included a range of different types; light horseman for scouting and pursuit, mounted bowmen for harassment, and heavy cavalry for shock action. The disaster of Hadrianopolis lay nearly a century in the future but the day of the horseman was clearly approaching.
But a lot of this is very speculative, and we'll talk about why when we start talking about the Sources, below.
Sources: We have, basically, four documentary sources for our knowledge of the battle that was fought at Milvian Bridge.
The earliest is a panegyric dated 313AD. This oration is supposed to have been given in Trier, one of many in the Roman tradition of praise-speeches to powerful men. This particular panegyric was collected in a manuscript known as the Panegyrici Latini, a total of 16 orations from the 4th Century and earlier; 12 complete and four fragments. This source is known from a single manuscript that was discovered in 1433 in a monastery in Mainz.
The primary importance of this work is that it appears to largely pre-date the official adoption of Christianity by the Roman government as the state religion. The orator appears to have been either a follower of the old Olympian gods or some sort of prevaricating pantheist. Other than Zosimus the contemporary accounts are explicitly Christian and, in particular, want to use the events of October 312 as a vindication of Christianity rather than an after-action report of a military engagement.
I also want to go into this particular manuscript a little to expand on why we are so unsure of the details of Milvian Bridge and many other pre-movable-type events.
The original 15th Century object, called the "M" (for Moguntinus) manuscript, no longer exists - it was destroyed, or misplaced, or eaten (who the hell knows?) some time after 1433. The cleric that found the MS, a man named Johannes Aurispa, made copies, and all the modern versions are descended from these. Two copies went to Italy; these are called X
These are ALSO lost.
A total of 27 manuscript copies were made from them before that were misplace, however. But the internal evidence suggests that Aurispa's original copy of M was not particularly good; either because he was just not that good a copyist or was rushed, or some other reason. This "lineage" is considered poorer than the other copies.
These are described as
"H and N are both fifteenth-century manuscripts, transcribed in a German hand. H shows corrections from a near-contemporary. N was copied at some time between 1455 and 1460 by the German theologian Johannes Hergot. Detailed investigation of the manuscripts by D. Lassandro has revealed that A derives from N and N derives from H. H is usually considered the best surviving manuscript." (Wiki, 2012)All these manuscripts contain errors and corrections; for all that the X versions are described as "inferior" the Wiki entry notes that "...when X
Get the idea? This manuscript stuff is extraordinarily chancy.
OK, so we have three other "primary" sources. Well, really two other primary and a sort-of secondary source
One of the two primary sources is a guy named Lucius Caecilius Firmianus Lactantius. The written work which gives an account of the engagement at Milvian Bridge is Lucii Caecilii liber ad Donatum Confessorem de Mortibus Persecutorium, usually referred to in English as The Deaths of the Persecutors.
Lactantius (as he is better known) was a career Roman bureaucrat. He first turns up as Diocletian's appointee to the faculty of the University at Nicomedia in about 300AD. He turns up next in 317 as tutor to Constantine's son Crispus.
Other that these meager details Lactantius is known only through his surviving writing, which is described as
"...more adept at showing the incongruity of heathen polytheism than in establishing Christian teaching...designed to present Christianity in a form that would be attractive to philosophical pagans. In practice this resulted in a uneasy amalgam of Christianity, Platonism, Stoicism and Pythagorianism. His views led to his posthumous condemnation as a heretic. Interest in his works was revived during the Renaissance not because of their outstanding theological content, but rather due to their "excellent Latin style".His de Mortibus Persecutorium is referenced hereafter as "Lactantius"
There are several issues with the Vita. Eusebius wrote to glorify Constantine, and consistently omits anything that tends to negate that. Some of this propaganda, such as his accounts of Constantine's campaigns against his fellow imperial wanna-be Licinius, is a outright lie. He also portrays himself as a much closer associate of Constantine than he really was. Still the Vita is perhaps the most complete work we have covering the events of 312.
The third source is the Historia Nova of Zosimus. This "new history", however, isn't a primary source; Zosimus was a Byzantine who lived more than a century after the events of Milvian Bridge, and gets his information about the events of the early 4th Century from the work of another guy called Eunapius, a Greek who lived in the second half of the 4th Century. Eunapius, at least, was a pagan and a pretty fierce one; what we have of his works are full of bile at the New Order, and Zosimus doesn't seem to take issue with that attitude.
What we know of Zosimus comes from a single 10th/11th Century Byzantine manuscript that currently resides in the Vatican.
Given the paucity of information about the battle proper it is nor surprising that there is little secondary writing that addresses the engagement itself. Two recent works turn up to a cursory search; a 2011 work titled Remembering Constantine at the Milvian Bridge (van Dam 2011) and Battle of the Milvian Bridge (Russell and Cohn, 2012).
Neither appear particularly useful for the student of military history. The former is described as a study of "...the creation and dissemination of the legends about that battle and its significance.", while the latter displays a large badge on the cover identifying its content as "High Quality Content by Wikipedia Articles"!
The Campaign: The road to Milvian Bridge really began with the Emperor Diocletian in 293AD.
OK, well, we actually need to start earlier, with the so-called "Crisis of the Third Century", an unholy mess of civil war and foreign invasion that nearly brought down the Roman Empire.
This little fracas is worth - and has been accorded - a full study, but to make it brief the Emperor Aurelian's forces managed to stabilize the Empire, but in the process Rome suffered great physical and economic damage. The troubles of the Third Century also made it clear that the Empire was now too big, and under too many threats, for a single administration to effectively control.
Diocletian "solved" this problem by inventing something called the Tetrarchy.
This involved setting up two "senior" rulers, each called Augustus with two juniors designated Caesar. This was emphatically NOT intended as a formal divison of the empire; these rulers were really the equivalent of military region commanders and their functions were more military than civil. The four rulers were treated as a sort of ruling Committee of Four, an "imperial college".
This worked out fine for about 20 years. But when the next couple of Caesars were appointed things pretty much went to hell.
One of the new augusti, Constantius, died the following year. In the reshuffle that followed Maxentius, son of the former Augustus Maximian, was odd-imperial-wannabe-out. He proceeded to raise an army, whip one of the tetrarchs and murder him, and declared himself an Augustus.
Maximian was supposed to retire, and Maxentius was, again, odd-man-out - he was declared a usurping bastard, all-around obnoxious party-crasher, and worthless git.
This worked like cement water wings; Maxentius took most of Italy and North Africa without any official title, and both Constantine and Maximinus had issues with that fucking noob Licinius as their superior.
By 309 the Senate had to make them Augusti, too.
Four Augusti did not bode well for the Tetrarchic system.
So between 309 and 312 civil wars or disease whacked most of the imperial wannabes.
The northeastern border and Gaul were always trouble spots; the orator of 313 claims that Constantine left the bulk of his forces along the Rhine, marching south with little more than a quarter of his troops (the number 40,000 is alluded to but may be a rhetorical device).
Regardless of the numbers the Constantinian forces beat the Maxentians like a drum all down north Italy. Turin fell, and then Verona; most of the battles are reported to have been as one-sided as Milvian Bridge would be.
Finally the last redoubt left to Maxentius was Rome itself, and the final battle would be just outside the gates of Rome, north of the Tiber across the Milvian (or Mulvian) Bridge.
Since I'm just that sort of person, a little history of the bridge itself.
Aurelius Victor says the original bridge was built in 110BC by the censor Aemilius Scaurus.
"When arrangements had been thus perfected and the night for the departure appointed, Cicero, who had been informed of everything through the envoys, ordered the praetors Lucius Valerius Flaccus and Gaius Pomptinus to lie in wait for the Allobroges and their company at the Mulvian Bridge and arrest them."Tacitus Annals say that by Nero's times the neighborhood was full of sleazy wine bars:
"The Mulvian bridge was then a famous haunt of nightly profligacy, and Nero used to go there that he might take his pleasures more freely outside the city."But perhaps the most famous bit of history involved in the campaign is supposed to have occurred the night before the battle.
Lactantius describes the "Vision of Constantine" thusly:
"At length Constantine, with steady courage and a mind prepared for every event, led his whole forces to the neighborhood of Rome, and encamped them opposite to the Milvian bridge. The anniversary of the reign of Maxentius approached, that is, the sixth of the kalends of November, and the fifth year of his reign was drawing to an end.Eusebius' accounts of this incident are more troublesome because they differ not just with Lactantius but with each other.
Constantine was directed in a dream to cause the heavenly sign to be delineated on the shields of his soldiers, and so to proceed to battle. He did as he had been commanded, and he marked on their shields the letter X, with a perpendicular line drawn through it and turned round thus at the top (P), being the cipher of CHRISTOS. Having this sign, his troops stood to arms."
In his church history (which was written within a short time after the engagement and before the author had encountered Constantine) Eusebius doesn't mention any sort of dream or vision, and doesn't mention any kind of Christian symbol carried by the Constantinian forces.
But in the Vita Eusebius tells a much more elaborate story, and one that is frankly not credible. He places the vision in Gaul, early in the campaign, and makes it happen at noon, on the march, where Constantine sees a cross of light over the sun with the Greek words "In this win!" (Τούτῳ Νίκα!).
Not just Constantine but the whole army sees this miracle.
That night Christ himself shows up - the ultimate Military Assistance Command, a sort of MAC-J - to advise the would-be Emperor to make symbols like the sky-light and thus ensure victory. Eusebius says that Constantine himself told this version late in his life.
Frankly, Connie or no Connie, the Eusebius version is just ludicrous. Such a public vision would surely have been reported by others, including the anonymous orator of the Panegyric and Lactantius (who as a fellow Christian and Connie-lover surely wouldn't have missed anything that would have looked so good on his boy and his faith...).
While the Lactantius version at least seems more "buy-able" we don't have any outside confirmation of his story, either.
The entire business gets more complex because of the lack of physical evidence. For example, the first archaeological evidence we have of this symbol (termed a "chi-rho" and, where used on a Roman military standard as a labarum) is on coinage from 317AD. Even then, there is some question of this as a purely Christian symbol; it had been used elsewhere as a manuscript editor's mark!
Certainly it appears widely in the conflict that Constantine fought against Licinius in the 320's, but it is nowhere in evidence on the Arch of Constantine constructed just three years after Milvian Bridge.
In early Constantinian coinage the sun-symbol of Mithras (that could also be interpreted as Helios or Apollo by Olympian-pesterers) was still present, not disappearing until after the defeat of Licinius in 325.
So while there seems to be some evidence that the engagement at Milvian Bridge might have been a "Christian versus pagan" encounter the evidence also seems by no means decisive. We'll talk about this more when we discuss the impact of the battle.
Right now, let's fight.
The Engagement: Here's what we're told about the actual Battle of Milvian Bridge.
Zosimus says that Constantine "encamped in a field before the city," (presumably part of the Tiber floodplain north of Milvian Bridge) "...which was broad and therefore convenient for cavalry." Zosimus gives the two army strengths as 90,000 infantry and 8,000 cavalry for the Constantinians while assigning a larger force to Maxentius; "...eighty thousand Romans and Italians, all the Tuscans on the sea coast, forty thousand men from Carthage, besides what the Sicilians sent him; his whole force amounting to a hundred and seventy thousand foot and eighteen thousand horse."
The crucial element of this engagement appears to have been construction of some sort of pontoon bridge by the defenders. Here's how Zosimus describes it:
"Both being thus prepared, Maxentius threw a bridge over the Tiber, which was not of one entire piece, but divided into two parts, the centre of the bridge being made to fasten with irons, which might be drawn out upon occasion. He gave orders to the workmen, that as soon as they saw the army of Constantine upon the juncture of the bridge, they should draw out the iron fastenings, that the enemy who stood upon it might fall into the river."Leaving out Zosimus ridiculous tale of owls flying down on Maxentius, we next find the two forces in combat order on the battle plain north of the bridge. Zosimus says that
"Constantine sent his cavalry against that of the enemy, whom they charged with such impetuosity that they threw them into disorder. The signal being given to the infantry, they likewise marched in good order towards the enemy. A furious battle having commenced, the Romans themselves, and their foreign allies, were unwilling to risk their lives, as they wished for deliverance from the bitter tyranny with which they were burdened; though the other troops were slain in great numbers, being either trod to death by the horse, or killed by the foot. As long as the cavalry kept their ground, Maxentius retained some hopes, but when they gave way, he tied with the rest over the bridge into the city. The beams not being strong enough to bear so great a weight, they broke; and Maxentius, with the others, was carried with the stream down the river."And that was that.
So what appears to have happened at Milvian Bridge is that the Constantinian cavalry engaged the Maxentians on both flanks and broke them. We can't be sure why this occurred, especially since failure seems to have struck the defenders quite quickly. It may be that the Rhine legion cavalry were better trained and more experienced, that their commanders were more capable, that the attackers were better motivated and led, or some combination of the above. But what seems clear is that here, as with the subsequent heavy infantry clash, the Maxentian troops did not fight particularly well.
Once their flanks had been turned the Maxentian center really didn't have much choice; it would be retreat to the river or be cut down from behind. This probably was in the process of happening when the Constantinian legionary infantry charged, and in short order the Maxentian force completely collapsed.
Greasy Grass in 1876, and at Adowa in 1894. In combat events can hang by a thread; in a moment retreat may become rout and defeat disaster. In this particular case Maxentius' dispositions ensured that disaster would be destruction, in that his forces could not retreat other than across the bridge (or bridges) to their rear.
The tradition states that the Praetorian Guard was the last Maxentian element to resist. This is not texturally supported; Zosimus, Lactantius, and Eusebius do not mention any of this "Guard dying but not surrendering" stuff. We can imagine that as the army unit most intimately associated with the defending ruler the Praetorians might have suspected that they would find little mercy in their conquerors, but this is pure supposition. And previous imperial spats had seldom resulted in wholesale slaughter of the losing troopers. At worst a handful of the senior officers might have met an executioner's dagger or strangling-cord.
I consider it likely that the Praetorians had formed around their emperor near the rear of the Maxentian array, and probably - once their commander sensed the flanks folding in - tried to edge back towards the bridge and keep their order. But a unit of several thousand in a rout of tens of thousands is unlikely to remain formed for long; it seems likely to me that the Praetorians were torn apart, small knots of troopers without officers and officers without troops in the swirling chaos, unable to do more than try and struggle towards safety.
Whatever the Praetorians were doing, their boss was attempting to get back inside the walls of Rome and failing. Somewhere in the clusterfuck on the Tiber Maxentius fell, or was pushed, into the river. With his lovely parade armor weighing him down he sank like a stone; supposedly his body was difficult to drag up but was recovered, as we have reports that his head was sent to North Africa to suppress the rebellion there.
The Outcome: Decisive victory for Constantine I with subsequent effects on the Roman imperium
The Impact: The immediate effect of Milvian Bridge was simply to consolidate Constantine's hold on the western part of the Empire. The Tetrarchy of Diocletian was effectively over, with two administrative and military divisions within the empire, East and West. In 325 Constantine finished reuniting the imperium under his control. His reforms, and his military victories, helped the Empire continue on for another several hundred years.
Zosimus says that Fausta was jealous of Crispus' ability and his father's favoritism in preference to her own sons (Crispus was the son of Constantine's first wife). According to the Zosimus story Fausta invented a tale of step-incestuous desire and attempted rape. Constantine murdered his son in rage and then, when Fausta's scheme came apart, had her killed as well.
That Fausta and Crispus were step-incestuous lovers.
That the bizarre "suffocated in a hot bath" method used to murder her was also an abortifacient intended to erase a fetus not implanted by her husband.
Whatever the truth, the year of 326 must have been a terrible one for Constantine.
The other people who disappear after Milvian Bridge are the Praetorians.
The Guard had simply become too dangerous to the Emperors. The ugly tradition of picking rulers that had begun with the machinations of Sejanus and Macro in the days of the Julians had become too imbedded.
Ironically, Constantine replaced the Praetorians with a huge body of troops, guard units called Scholae and Palatini, and overall with a comitatus - a personal field army - that far exceeded the household troops of the earlier imperium. Some scholars think that the Constantinian comitatus reached a quarter of the total imperial force.
The reasons for this are still debated. Some believe that this represented a recognition of the need for a large central reaction force in light of the increased likelihood of successful border incursions. But other researchers think that this was a more sinister reaction to the increased risk of internal treason.
Constantine made sure that the growing Christian movement got official recognition early on; in 313 he co-signed a law that made Christianity legal, as well as giving special recognition to the churches and individual Christian citizens.
This was important, not for religious reasons but for political.
Christians were prohibited from their religion from accepting and publicly attesting to the divinity of the Emperor.
They were also a source of social and political friction; the Roman Empire had existed for centuries by being publicly indifferent to religion.
lares and penates were the more-or-less "official" gods of the Roman state that state had no interest in how its subjects scratched their religious itches, so long as those itches didn't make the state break out in hives.
The Christians did; both by fussing about others' worship AND denying the divinity of the Emperor.
The Edict of Milan elided this problem, rather than solved it.
What did "solve" in, in a sense, was that Constantine bought into the idea of using Christianity as a political tool. He was the first Emperor to recognize that the empire could be stronger with the Christians inside the tent pissing out. Over the next century Christianity (of one sort or another - the century after Milvian Bridge was full of Christian on Christian conflict) became the official religion of Empire, and so the Christian hagiography and mythology makes Constantine a captive of Christ, the first Christian ruler and saint.
But in a larger sense it is Rome that captures Christianity.
lays this out in detail:
"One of the first things Constantine does, as emperor, is start persecuting other Christians. The Gnostic Christians are targeted...and other dualist Christians. Christians who don't have the Old Testament as part of their canon are targeted. The list of enemies goes on and on. There's a kind of internal purge of the church as one emperor ruling one empire tries to have this single church as part of the religious musculature of his vision of a renewed Rome."The result is a Church, and a religion, that becomes more like the state that is is supposed to have taken and the Empire less like the Christ of the gospels; there is little interest in meekness and poverty, much in strength and wealth. This little anecdote by the same author is revealing:
"[T]here's a beautiful mosaic in Ravenna, a city in northern Italy, which I routinely show my classes. It's of a beautiful, very handsome, well muscled, beardless man. He's dressed in a Roman officer's uniform. And he's stepping on the head of a lion, and he's holding a standard. And the standard says in Latin, "I am the way. The truth. And the life." And usually my students can't read Latin and I say, "Who's this a picture of?" And they guess, "The Roman Emperor." But it's not. It's a picture of Jesus."And there you have it; the Jewish rabbi, who died on a criminal's cross for preaching his Father's insistence that true power and glory came from weakness, submission, and faith has become a resplendent soldier in the armor of conquest, bearing a standard instead of his cross.
The stone the builders rejected has become the capstone in a military gate, and the projectile cast by a war engine.
If there is a better moral from the opaque history of Milvian Bridge I cannot find it.
Touchline Tattles: from the Wikipedia entry on Ponte Milvio; "love padlocks":
After April 13, 2007, couples had to stop this habit because that day the lamppost, owing to the weight of all padlocks, partially collapsed. However, couples decided to lock their padlocks in other places. In fact, all around the bridge, road posts and even garbage bins have been used to place these love's padlocks.
As an online replacement, a web site has been created allowing couples to use virtual padlocks.
placed new steel posts on the old bridge so that Roman couples might continue to lock the symbols of their love and fidelity in the place where the might of Imperial Rome first began to subdue the Son of God.