The Late Roman Army - Reforms, Strategy and Class System of the 4th Century

Starting at the end of the 3rd century, the Roman Empire underwent a phase of complete overhaul, both in terms of its civic administration as well as its military. Emperor Diocletian was the main instigator of all this. During his rule, the frontiers were extensively fortified and the number of soldiers was drastically increased. But the most fundamental change to the late Roman military is estimated to have taken place, at least formally, just after the rule of Diocletian. The change I'm talking of brings about a completely new hierarchical structure to the army, introducing classes, each with its own rights and privileges, but also a specific role to fulfill in the bigger picture of late Roman warfare. This system would truly change the old way of operating for the Roman army and would remain valid for centuries to come still. To understand late Roman warfare, this is the only right I want to take a quick moment to tell you about today's sponsor, World Anvil. 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And if you're more of a tag-along roleplaying gamer like me, World Anvil is amazing to keep by your side as well, because it has all the rules for more than 80 of the most popular roleplaying games, where you can build and keep track of your character and its stats, items, skills and resources, as well as the information the game master has granted you access to. So, if you're looking to create any sort of story or world, or enhance your roleplaying experience, be sure to check out World Anvil. Visit worldanvil.com and use the code from the description below, Romanum, to get 51% off your yearly subscription. To fully grasp the impact of this change, it's important to have an understanding of the relevant context and background. So, allow me a quick introduction. During the first two centuries of the empire, there was a decisive classification in the army between legionary and auxilia units. The legionaries were recruited from Rome's own citizens, and served in legions, units of roughly 5,000 men. In the auxilia served people without the legal status of Roman citizenship. In practice, that meant that these were made up of all sorts of foreign allies, defeated enemies, or tributary states and tribes. To the Romans, most of these simply qualified as barbarians, and they were in some regards treated as such. They received a lower pay and were not allowed to vote, amongst others. It was in the year 212 AD that these differences were finally removed. In that year, the emperor Caracalla decreed that all inhabitants of the Roman Empire would from now on be Roman citizens, thereby making auxilia and legionary equal in all but name. This meant that the traditional ethnic Romans could now be recruited for service in auxilia units and former non-Romans, barbarians, just as well for service in the legions. With the passing of generations and units travelling around and being refilled with local recruits, the traditional distinction in ethnicity between auxilia and legionary would have rapidly vanished. This fading of once clear lines occurred not just in the military, but also in civil life all around the empire because the old barbarian provinces had, by the time of the 4th century, been Roman for roughly 300 years, resulting in the inevitable blend of all aspects of life, language, culture, religion, fashion, food, etc. So, for understanding the late Roman Empire, we really have to let go of our traditional view of the Roman world that is strictly split up in Roman and non-Roman, where the people are either Roman or Gallic, Roman or Germanic for example. Instead, it was now Roman and Gallic, Roman and Germanic. The Roman identity was no longer as tightly defined and exclusive, but instead as mixed as the people inhabiting the empire. The last functional difference between legionary and auxilia remained in their deployment. Historically, both the legionary and auxilia units were stationed along the frontier, the legionaries in their entire 5,000-man units, and the auxilia more dispersed over a longer stretch of the frontier, manning the smaller forts and watchtowers. Both, however, fulfilled similar roles. On the one hand, they protected their part of the frontier, and on the other hand, they also partook in the bigger military operations. If they were called upon for any such major campaign, they would send detachments or reserves from their ranks, together forming an army. This obviously weakened the border they left behind, and it also impacted the stability in the local community, where they were employed for policing, customs, and other public duties. Exactly this way of operating is what changed in the 4th century. No longer would all units have similar and fluid roles. Instead, the army was now divided into units that were part of the mobile field army, for the bigger military operations, the comitatensis, and into units that were permanently garrisoned along the frontier and responsible for the border security, the so-called limitanai. There is also a third class, with a slightly different role, but we'll get to that later. Let's start with looking at the core of the system, that is, the border troops and the field army. First up are the border troops, the limitanai. Their name is clearly derived from either the word limes or limites, both used by Romans to refer to the frontier of the empire. And so, limitanai simply translate to something like border men or border troops. And correspondingly so, they were responsible for policing and defending the border regions, and were stationed in forts and watchtowers along the frontier. Amongst their ranks, cavalry was more prominent, because their mobility was great for patrolling and intercepting of enemies. A similar class of soldiers for border security, but specifically tied to guarding the river frontiers, were the so-called ripenses. Both of these served under a regional military commander called a dux, giving us the word duke. His sphere of command could cross multiple provinces and was independent of the vicari, the local governors, since military and civil powers had been strictly divided in the early 4th century. So much for the limitanai for now, what about the mobile field army? The word comitatenses is clearly derived from the word comitatus, used to refer to the household of the emperor. In the early empire, this entourage consisted mostly of the emperor's personal advisors and friends, but over time, grew to include more military officers and also bodyguards, either individuals or entire regiments, handpicked by the emperor. In the 3rd century especially, the imperial bodyguard grew ever larger, since the threat of usurpers to the throne was always right around the corner, and so the emperor would keep his personal army close and large. Herein lay the origins of the 4th century class of soldiers called comitatenses, and, probably by emperor Constantine, these troops got formalized into an official class that was no longer necessarily connected to the imperial bodyguard. They were since under command of either a comus, translated to count, or one of the highest-ranking military commanders, a magister militum. With the limitanai and repenses acting as the all-round border security, the comitatenses filled the part of the field army employed specifically for large-scale operations, both offensive and defensive. But, of course, such large operations were not continuous, at times there would simply be no action for such a force. In such times of inactivity, these comitatenses troops had to be stationed somewhere, and in the 4th century it became more and more common for soldiers to be quartered in with civilians. This is particularly applicable to the comitatenses, it seems, because the limitanai were garrisons in forts and watchtowers along the border. Because the limitanai were stationed along the frontier, many historians assume the comitatenses, therefore, were not, but instead were stationed further inland. This assumption forms the basis for the so-called defense-in-depth strategy, which has grown out to be one of the most widely accepted but unsubstantiated ideas when it comes to late Roman warfare. According to this theory, the late Roman empire had this grand strategy where the limitanai fought off the smaller bands of raiders and invaders along the border, and the comitatenses were deliberately stationed further inland, acting as a sort of quick response team for any foe that couldn't be stopped by the limitanai. Although the theory itself doesn't necessarily seem implausible, there's simply hardly any evidence to support it. Without losing ourselves in the details, in our view, it seems most likely that there was no specific area where the comitatenses were stationed. It might be somewhere in the interior, far away from the frontier, for peacekeeping duties for example, but just as well in camps, fortifications, and cities along the border, and just as well mixed in with limitanai units, wherever and however was fitting for the local situation. The Romans, after all, were highly pragmatic when it came to warfare, and didn't form any rigid, single-minded overall grand strategy to be applied all over the empire. So much for the operational aspect of late Roman warfare. Besides their combat roles, there is another clear distinction between the limitanai and comitatenses and that is their class. Their class would derive from the rewards and privileges tied to either one of them. Accordingly, we can say that the comitatenses were of a higher class than the limitanai. They received a higher salary and enjoyed better conditions regarding tax exemptions, service and leave, promotion, and discharge. These classes are often interpreted as an indicator for quality, whereby the limitanai are considered the lesser of the two and thus less deserving of certain benefits. What has greatly contributed to this idea is the fact that the Codex Theodosianus, a collection of laws from the 4th and early 5th century, mentioned that the limitanai were allowed a plot of land to cultivate. This has greatly contributed to the misconception that they were sort of second-class soldiers, even some sort of peasant militia, and not full-fledged soldiers like the comitatenses. In the last decade, this view has started to shift, and the limitanai are finally getting recognized as professional soldiers. There's tons of arguments for this, but the most compelling is the fact that units from the limitanai were often employed in major campaigns, either temporarily, whether or not under command of their own dukes or jointly with the comitatenses, or permanently along with the comitatenses, which is where we get the word pseudo-comitatenses. These major employments would not be common practice if they weren't also professional and capable soldiers. The question remains though, what is then the reason for that higher pay and additional benefits of the comitatenses compared to the limitanai? Well, the reason for that might very well lie in that plot of farmland the limitanai were allowed to cultivate. Once again, a clue is given by the codex, which explicitly speaks of cultivating for their own profit. This profit, whether income from selling their produce or lower spendings on food, represents an economical value, which could be reflected in a lower salary. Another reason for the overall lesser position of the limitanai might lie in their working environment. In contrast to the soldiers of the comitatenses, the limitanai were stationed in a fixed location, possibly close to home, and surely had more comfort and stability in their life. This was likely all factored in their pay and class, since class was mostly a package of benefits in its own right. Above the regular comitatenses, at the top of the hierarchy, were the palatina. Although they are easily mistaken for a separate class, they were actually part of the class of comitatenses, but a higher rank within that class. With that, they were the highest ranking soldiers and are often regarded as elite. So what and who were they, what was their role, and how special were they exactly? To begin with their origins, the word palatina is derived from the word palatium, palace. And so, obviously, these are palace troops, in direct service of the emperor. But in practice, they served under one of his representatives, being the highest military commander, the magister militum, the master of soldiers. Because the empire had since Diocletian's rule around the turn of the century been divided into two separate administrative parts, both the west and the east had its own palatine army under command of one or more magisters. The function of the palatina was to act as an emergency response army, much like the comitatenses acted on a more regional scale. So, they were employed for the biggest of military operations, think all-out wars. It all goes to show that our modern perspective of strictly outlied job descriptions and roles cannot be blindly applied to ancient times. Things were generally just a lot more ad-hoc and fluid, though not when it comes to the system of classes. There were severe punishments for unjustified promotions from one class to the next, as allowing fluidity in this regard would be an open invitation for corruption. The palatina now took over the position of highest ranking soldiers in the Roman army, and their high rank showed accordingly in their rights and privileges. Compared to the comitatenses, the palatina received an even higher salary, enjoyed even more tax exemptions, were eligible for certain higher command posts, like that of a tribune of a cohort or supervisor of an armory or fleet. They were granted exceptions from certain compulsory public services, and they even received their own grade of food rations. These are the proper rights belonging to an elite status, much more so than that of the comitatenses over the limitinae. Whether or not that status was reflected in their equipment as well, is highly doubtful. In the late Roman Empire, equipment was produced en masse in state-organized and centralized factories, and thus relatively uniform all across the board. The higher ranking soldiers no doubt received first pick, but this wouldn't result in any significant differences between the units. It is also highly unlikely that these factories produced different qualities or variations of the same item, but just for different units. Neither are there any indications that point to different units being equipped differently, besides obviously archers and cavalry. This wouldn't make sense either, as the work of the limitinae and the comitatenses was just as vital for the stability and safety of the empire as that of the palatina, so why disadvantage them on purpose? But there is one other reason that might have led to the palatina standing out amongst the other troops, and that relates to their higher salary. Their bigger purse allowed them to spend more on custom made equipment, a particularly nice belt, helmet or sword for example. So, the palatina might have worn somewhat different, more expensive, prettier and slightly better equipment than the lower ranking soldiers. But overall, the difference between these palace troops and the others was probably barely recognizable to outsiders. In practice, this system wasn't all that rigid, and it often happened that troops were transferred from one region to another or from one role to another. Like we said before, the limitinae for example could be employed as pseudo-comitatenses, and the other way around, the comitatenses could gain a more or less permanent deployment along the frontier as border security just as well. And the same surely goes for the palatina. We know that quite some of the regiments were employed as comitatenses in a fixed province for example. For the palatina especially, their flexibility went even further than solely military duties. One colorful example of such comes to us from the Codex Theodosianus, which state that watchful and diligent members of the palatina are to be stationed in certain places to check whether carriages don't surpass the maximum load they were allowed to carry by law. Similarly, they were also burdened with escorting official carriages up the public postal service. Does that mean the palatina were in no way better or different than their lower-ranked colleagues? Well, not by their training, equipment, or battlefield role, but maybe in battlefield performance. Because the status and many benefits that came with being a palace soldier might in itself form an extra motivation. Besides that, some units were promoted to palatina precisely because of the exceptional performance in battle, and thus predisposed to outperform others, one might think. By far, the majority of units of palatina however, were not promoted to this class because of their performance. Instead, many were simply formed from leftover praetorian units and legionary detachments. Others again, were completely new and recruited straight into the palatina. Many of these new units were raised during the rule of emperor Diocletian, by himself as emperor in the east, or by his co-emperors in the west. Because Diocletian was a hardline conservative, he may have named his units legions, while in the west, with a long history of supplying great numbers to the auxilia, the units were named auxilia. After all, there was no legal difference anymore between the two. Whatever the reason, the notitia dignitatum, an overview of military offices and units in the early 5th century, lists virtually all auxilia palatina units as either serving in the west, or by their name can be traced back to the west. Peculiar enough, these units of auxilia palatina had a different ranking system for their under-officers, and so did not have the traditional rank of centurion amongst others. Other than this peculiarity, there's no reason to assume the auxilia palatina were any different from the legionary palatina, especially as time went by and whatever it was that may have distinguished them originally faded or diluted. That concludes our overview of the late Roman military class system. It's a system that is often dumped down to the simple differentiation between frontier troops and the field army, which is then interpreted in a straightforward manner that makes sense to us on paper. But as you can tell by now, there's a lot more complexity to it, and we're still guessing in the dark about a lot of things. The overall efficacy of the system seems questionable though, considering that in reality troops regardless of class were employed for whatever role was required of them. The system also didn't create some type of elite soldier, as is often suggested. In fact, the soldiers of the 4th century are more uniform and similar amongst each other than ever before, now that even the difference in auxilia and legionaries was gone. Perhaps the most value of the system really was on paper, which would be in line with so many of the bureaucratic efforts to overhaul and save the empire in the 4th century.