Did the Roman Principate during the 2nd century field the best army in the world?

Mar 2018
890
UK
The problem is basically one of preconception. Firstly, we're guided by our ideas of modern military expectations and please note how easily people compare ancient and modern in that context. Secondly, a great deal of commentary on the legions starts from the idea of their military excellence. Well, they were certainly capable of making an impression, yet documentary evidence suggests this was not uniform. After all, they did not even have uniform appearance in the manner we typically portray them - shield shapes varied between legions and in one source (Stratagems by Frontinus if I recall correctly) a legate criticises a soldier for his elaborate painting of his shield - "He cares more for his shield than his sword"

Since the Roman legions were not regiments of an army organisation (they were all independent packets of military power assigned to politicians to further security) we ought to look closer at relative performance and loyalty, important issues to them politically but less to us when enthusing about excellence.

Thirdly, concerning discipline. In modern terms we expect "organised good manners". Observance of rank and authority, esprit de corps, behaviour (though we all know soldiers have a tendency to misbehave :D). In Roman terms, their discipline was harsh and not always consistent. Basically they wanted obedience and steadfastness. usually, as with most pre-20th century militaries, they got what they wanted because the soldier was more afraid of punishment than misbehaving. Nonetheless, the sources are quite clear. Roman soldiers did rout. One of the tasks a senior officer concerned himself with in battle was not necessarily directing them, but standing behind a wavering unit pushing men back into line (Caesar describes this in his Gallic War commentaries). A leader might well fight in the front line alongside his men.

Still, we can see why this mattered. A Roman legionary can be executed for refusing an order. He can be flogged for petty offences. Their regime, as Josephus confirms, became one of constant practise when legions were properly led. But were they the best? More difficult, because our impressions of Roman soldiers are from the Romans themselves. We have little comparative evidence.

I'm reminded of an anecdote from Plutarch. During the fighting in Britain a legionary spotted a group of centurions under threat from British warriors. He ran to their rescue across the marsh, dropping his shield (a serious punishable offence) and saving the day. Caesar saw what happened and summoned the man to him. The soldier arrived and dropped to his knees, begging for mercy. Caesar wanted only to congratulate him for his bravery.
Thank you for the list of independent anecdotes and factoids. But what is, in the context of this thread, your point?
 

caldrail

Ad Honorem
Feb 2012
5,330
Sorry, I thought it was obvious. The thread asks a question that at first glance suggests a purely military response. Were they effective in hostilities or not? This however ignores important factors that someone more familiar with modern practice might not know of or appreciate. So perhaps it's worth looking at the principatal legion from a slightly different perspective.

We're talking about military formations used as an adjunct to political purposes. Or at times, literally forcing a political ambition themselves, independent of national requirements or those of other legions. We're talking about a military that published a scale of standard bribes to avoid unwanted duties (Annals Tacitus), and that despite some efforts in later centuries, corruption was never eradicated. Indeed, we know that money was essential for proactive operation on a daily basis ("Nothing happens around here without money" from soldiers letter recovered in Egypt). We know that low level disputes and complaints about the military regime were commonplace (Annals Tacitus) though full scale mutinies were much rarer. We know that senior officers went to great lengths to keep veterans beyond their normal retirement instead of finding new recruits (Lives of the Caesars Suetonius). We know that up to half the legion might be on leave at any given time (Letters, Vindolanda). We know that soldiers routinely 'requisitioned' whatever they wanted from civilians, that complaints from the public were heard by military tribunal that was sympathetic to the soldier and indeed risked the complaintee getting beaten up for daring to seek justice (various sources including satires). We know that at times legionaries even mounted bandit raids on settlements for their own gain (Various, including Annals Tacitus). The soldiers expected, after victorious occupation of a settlement, to loot and pillage freely as a reward for their risks.

it creates a colourful image of Roman military life that the original questioner probably never considered. I've said in the past that at their best a legion was good and you can't get away from it. At their worst, shockingly bad by modern standards.
 

aggienation

Ad Honorem
Jul 2016
9,813
USA
It seems that most of the answers so far in terms of the efficiency of the Roman military focus on the *Roman* element, IE I assume the legionaries/ infantry. a question that just came to mind regarding Roman military performance in the 3rd century- is there an argument that at that stage Roman military efficiency was optimised, compared to previous eras (I'm thinking of the late Republic and early Principate, I suppose), because of the wider availability of subject/allied contingents to act as auxilliary cavalry? IE the late Republic had gauls and possibly Germanic auxiliaries too, but by the 3rd century Rome also had Sarmatians/ Pannonians/ Parthian auxilliaries, that they did not have access to in earlier periods?
Cost of citizen cavalry is one consideration brought up recently by some modern historians to try to explain why Rome stopped using citizen cavalry in the Late Republic. The lowest cavalryman was paid the salary of a centurion, and it went up from there. An auxiliary cavalryman was not paid, they served as tribute to the Romans, who were only responsible for their food/fodder and a small percentage of the proceeds of loot.

Besides, choosing foreign auxiliary who lived near the conflict area meant it was cheaper to move them too, as it meant less ship transports, or not having to supply them for the hundreds of miles of marching from Italy to wherever.

It was similar to Roman velite, who also disappeared around the same time. Why pay a skirmisher the same as a heavy infantryman when a Balaeric slinger or Cretan archer or other foreign auxiliary can do the job cheaper? Why ship a Roman javelineer hundreds of miles to do the job a local ally can do cheaper?

The one job they couldn't truly outsource in the Republic and early Principate was heavy infantry, but even by the 1st Cent AD and after auxiliary heavy infantry seem to be just as good, if not occasionally better, than citizens.
 

Dan Howard

Ad Honorem
Aug 2014
5,000
Australia
IMO the Roman army reached its peak after the Diocletian reforms. For the first time everything was centrally controlled, standards were strictly enforced, and they had rigorous quality control. Military equipment, organisation, and logistics were arguably the best the Romans ever had. Look at the military successes of the tetrarchic army (290-305 AD). The Romans had never before had such a succession of victories against such a range of foes.
 
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mariusj

Ad Honorem
Aug 2015
2,019
Los Angeles
IMO the Roman army reached its peak after the Diocletian reforms. For the first time everything was centrally controlled, standards were strictly enforced, and they had rigorous quality control. Military equipment was arguably the best the Romans ever had. Look at the military successes of the tetrarchic army (290-305 AD). The Romans had never before had such a succession of victories.
Wasn't Hadrian famous for his qc and drills?
 

mariusj

Ad Honorem
Aug 2015
2,019
Los Angeles
That doesn't mean that the army in his time was better than Diocletian's.
Wouldn't Trajan-Hadrian period also have similar kinds of drill, QC, and succession of successes as well, and Trajan and Hadrian govern over a much more unified empire both in administration and in spirit?
 

Dan Howard

Ad Honorem
Aug 2014
5,000
Australia
Wouldn't Trajan-Hadrian period also have similar kinds of drill, QC, and succession of successes as well, and Trajan and Hadrian govern over a much more unified empire both in administration and in spirit?
That was the intent but not the result. Without reforms such as those instituted by Diocletian, anything Hadrian wanted to enact would be half-arsed at best.

The tetrarchy had greater victories against far more formidable foes. Considering the deplorable state of the Empire when he took power, his success was nothing short of remarkable. Diocletian's reforms and military victories allowed the Empire to continue for another 150 years.
 

mariusj

Ad Honorem
Aug 2015
2,019
Los Angeles
The tetrarchy had greater victories against far more formidable foes. Considering the deplorable state of the Empire when he took power, his success was nothing short of remarkable. Diocletian's reforms and military victories allowed the Empire to continue for another 150 years.
I think the state of the Empire isn't as bad as people generally assume it to be. The fracture allows local Roman authorities preserve Roman territories without worrying about the bigger pictures that don't affect them, so when Aurelian unified the empire it wasn't like the empire was crumbling, in fact, we can argue that towards the end of Gallienu's reign the Roman world in large has stabilized from the disasters of the Third Centuries and recovered from the series of military defeats that began with perhaps the rise of Philip the Arab.

The Gallic Empire was able to maintain it's integrity and repel in general Frankish incursions, the Empire itself was able to push back all kinds of raid and Odaenathus was able to resist the Parthians. There wasn't a lot of fighting to unify the empire, far less than previous civil wars, and in the end you have a stable empire that is suffering from the economic effect of Gallienus' devaluation but military wise it wasn't like it's rotting, we can even say that the forces under Aurelian was better than the forces Gallienus had after decades of warfare and officer corps been experienced and capable.

Diocletian inherited that same kind of officer corp as well as an empire that was stable if not for the declining economic activity part. I don't know if Diocletian inherited a 'worse off' empire compare to every founder of the dynasty except for Trajan. There weren't any opposition to him either in the civilian world or the military world. He had so much control he could ignore Rome for like 2 decades.

Granted, Trajan and Hadrian both had a way better start than he did, I just don't think his forces are superior to those under Trajan and Hadrian. They are probably on par in terms of effectiveness at least towards the later period of Trajan's reign and Hadrian's reign.
 
Oct 2018
1,852
Sydney
I think the state of the Empire isn't as bad as people generally assume it to be. The fracture allows local Roman authorities preserve Roman territories without worrying about the bigger pictures that don't affect them, so when Aurelian unified the empire it wasn't like the empire was crumbling, in fact, we can argue that towards the end of Gallienu's reign the Roman world in large has stabilized from the disasters of the Third Centuries and recovered from the series of military defeats that began with perhaps the rise of Philip the Arab.

The Gallic Empire was able to maintain it's integrity and repel in general Frankish incursions, the Empire itself was able to push back all kinds of raid and Odaenathus was able to resist the Parthians. There wasn't a lot of fighting to unify the empire, far less than previous civil wars, and in the end you have a stable empire that is suffering from the economic effect of Gallienus' devaluation but military wise it wasn't like it's rotting, we can even say that the forces under Aurelian was better than the forces Gallienus had after decades of warfare and officer corps been experienced and capable.

Diocletian inherited that same kind of officer corp as well as an empire that was stable if not for the declining economic activity part. I don't know if Diocletian inherited a 'worse off' empire compare to every founder of the dynasty except for Trajan. There weren't any opposition to him either in the civilian world or the military world. He had so much control he could ignore Rome for like 2 decades.

Granted, Trajan and Hadrian both had a way better start than he did, I just don't think his forces are superior to those under Trajan and Hadrian. They are probably on par in terms of effectiveness at least towards the later period of Trajan's reign and Hadrian's reign.
I agree that the third-century Roman army had adapted from the mid-century disasters to be pretty damn effective, but in terms of usurpations and assassinations Diocletian could not have expected to last very long. It strikes me as being quite incredible that he ruled for more than twenty years and then enjoyed a peaceful retirement. The only emperor who lasted for a similar length of time in the late third century was Gallienus, and he had to cede control over the empire's north-west and (de-facto) the near east. Diocletian kind-of ceded control as well, but he maintained seniority, he alone ordered empire-wide edicts, he chose his co-rulers, and so on. In short, he did a remarkable job of getting things done at a time when he should have been killed within a few years. I do think that the biggest challenge facing Diocletian when he came to power was military and provincial rebellion, and indeed I suspect the Tetrarchic arrangement, in addition to being a scheme of succession, was largely intended to provide the different frontiers with a present emperor to watch over the armies and their officers and attend to their needs. Indeed, two of the biggest challenges that Diocletian and his colleagues had to confront was the usurpation of Carausius and Allectus in Britain and northern Gaul, and the usurpation of Domitianus and Achilleus in Egypt. That said, there were also plenty of foreign enemies to deal with (Franks, Alemanni, Sarmatians, Carpi, Blemmyes, Nobates), and Galerius' victory over the Sassanians, which saw the addition of seven trans-Tigritanian territories among other benefits, was a decisive encounter won against an enemy that appears to have been tougher and more determined than the Parthians (it was also a nice bit of vengeance after the mid-century defeats to Persia, although I acknowledge that Odainath and Carus also won notable successes in this regard).

Also, Dan Howard is referring to the fact that the empire of Diocletian was more centralized in an administrative sense. Yes there were four emperors, but the imperial administration under these four was much much bigger than it had been under Hadrian. I'll quote R. Smith (2011: Measures of Difference: The Fourth-Century Transformation of the Roman Imperial Court, American Journal of Philology 132: 125–51) 135-136: 'The sheer human size of the late court is also telling, and here, too, Diocletian's reforms are a hinge. The doubling of the number of the empire's provinces to around one hundred, grouped into a dozen newly created "dioceses," fuelled a boom in the number of its administrative offices; and over the fourth century, the banding of dioceses within territorial praetorian prefectures would create still more offices. In the mid third century, it has been estimated, there had been around three-hundred salaried senior civil servants to administer the empire, working with clerical assistance of (at most) 10,000 slaves and freedmen of the imperial household. Estimates of the total size in the late fourth century, by contrast, put it at around 35,000, of whom perhaps as many as 6,000 held "upper-level" posts that presupposed senatorial status or automatically conferred it.'

Diocletian was also an exceptionally hands-on ruler, which added to the increasingly pervasive presence of the imperial administration(s). A couple of quotes from David Potter:

Potter (2014: The Roman Empire at Bay, 2nd ed.) 292: ‘It is under Diocletian, as well, that the old form of the imperial edict, a general statement of policy addressed either to the empire as a whole or to a specific group within it, becomes far more common than it had been in previous ages. Diocletian plainly saw the administration of justice as a zone in which the emperor should function to create a new order in society. The attempted transformation of societal norms through imperial fiat was a process that gained in speed as the reign went on.’

Potter 329: ‘In general historical terms, the persecution edict is perhaps of greater significance as evidence for the activist stance of tetrarchic government, a stance that was inherited by the governments that succeeded it. This belief in the power of central government to effect sweeping change stands in stark contrast to the style of government in the first two centuries AD, where, for instance, one emperor’s decision about the definition of colonial status would not change preexisting statuses. There are obviously precedents in the course of the third century, ranging from the constitutio Antoniniana, to Decius’ edict on sacrifices, to Valerian’s persecution edicts, to the currency reform of Aurelian, but no period in the history of Roman government offers so many examples in short order as occur in the reign of Diocletian. Unlike previous emperors who might work within existing structures, amending certain practices in, for instance, the collection of taxes, Diocletian often appears to be trying to sweep all these earlier practices away. The language that his government used was usually deeply traditional in form, but outward form is not the same thing as intent. The ideology of reconstruction that informed tetrarchic reshaping of the historical level was not empty. The rhetoric offered a justification for major efforts at actual change.’
 
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