Artillery of Roman Legion

AlpinLuke

Forum Staff
Oct 2011
27,235
Italy, Lago Maggiore
Is this based on anything other than Trajan's Column?
About the usage on a chariot of the scorpio, I'm aware of that representation. Regarding the usage of that weapon in a "sniper style" there are several chronicles reporting this.

The "De bello gallico", for example, reports that the Gauls, defending a position during a Roman siege, kept on substituting the warriors killed by the accurate darts of a scorpio.

Liber VII, 25.
Quidam ante portam oppidi Gallus per manus sebi ac picis traditas glebas in ignem e regione turris proiciebat: scorpione ab latere dextro traiectus exanimatusque concidit. Hunc ex proximis unus iacentem transgressus eodem illo munere fungebatur; eadem ratione ictu scorpionis exanimato alteri successit tertius et tertio quartus, nec prius ille est a propugnatoribus vacuus relictus locus quam restincto aggere atque omni ex parte summotis hostibus finis est pugnandi factus.
In good substance there was a Gaul launching balls against the besiegers and he got killed by the scorpion. Other Gauls substituted him meeting the same destiny.
 

macon

Ad Honorem
Aug 2015
4,107
Slovenia, EU
I'm curious to know if
1) the artillery was initially deployed in front of the friendly infantry and shot at the enemy while still far off, then when the enemy drew closer the artillerymen fell back through the infantry ranks or
2) the artillery deployed behind the friendly infantry and shot over their heads with indirect fire or
3) the artillery deployed on higher ground behind the infantry and shot over their heads in direct fire mode or
4) some other tactic and deployment mode
3 would be my choice. Or on flanks.
 
Mar 2018
861
UK
The scorpion [scorpio] was quite little, accurate and mobile. This actually allowed the Romans to deploy "snipers" ante-litteram. And they were trained to use it from a chariot [so moving around the battlefield]. A legion carried about 60 scorpions with it and it accuracy was well known among the enemy of Rome. Within a range of 100mt it was able to wound or even kill with a single hit. The scorpions stayed behind a protection of infantry and 60 of them fired about 240 bolts per minute.
That seems to be the paper figure, I'd surprised if this actually happened regularly in practice or if even this paper strength persisted for centuries. And, again, is there any evidence for carrobalista besides a single image on a single column? If they were really all that useful and widespread, why do they not appear everywhere in descriptions of battles? I also don't believe in shooting from behind friendly lines. If you consider the depth of a cohort, the multiple lines of cohorts and the gaps between the lines, 100m is not so long. And besides, how would fire control work? The operators wouldn't be able to see what they were aiming at: what happens if you have your own skirimishers in front, or the first line of cohorts pushes forwards more than expected, or your cavalry is flanking the enemy? It's going to take some very robust evidence to deal those major hurdles.

Still, even with these idealised figures, this makes a scorpion about as deadly as, say, a longbowman. Scorpions would have had better armour penetration probably, but I'm not sure how important this is if you can go through most armour already. So the scorpion contingent of a legion would be roughly the same as having 60 medieval longbowman teleported in, but slower to move around and requiring multiple men to use. Useful in some situations, but a drop in the ocean compared to some 4500 heavy infantry.

There are only a few situations where I can see them being really useful. As stated before, in sieges, attacking or defending; this should be obvious. The other would be area denial. Say you want to cross a river, but archers on the other side are rudely shooting at you as you attempt to cross. You put your own scorpion/ballista on your side of the river, outrange the enemy archers, and take pot shots at them until they see the wisdom of taking a few steps back, thereby letting your vanguard ford the river more safely. A variant of this is to force the enemy out of a defensive position. If they are formed up on top of a hill and you want to dislodge them, a frontal assault would be difficult. But you can deploy your artillery in the front rank and start shooting. They can then respond in three different ways. Firstly is to just stand there, and slowly die (this is the worst option); secondly they can retreat from their strong position, thereby granting you your objective. Or, thirdly and most likely, they'll have to leave the hill and close with you, at which point your infantry steps in front of the scorpions and fights as normal. Note that in these cases the scorpions don't have to fire a single shot to be effective, by giving the Romans a wider set of tactical options, they force the enemy to react.

But these are relatively specialised situations. If they were very helpful in standard pitched battles/meeting engagements, then where are the historical texts describing their use in every battle? It's all well and good to theorise, but if there is scant evidence that ballista/scorpions were routinely used to great effect, then they probably weren't routinely used to great effect.
 
  • Like
Reactions: macon
Oct 2018
1,725
Sydney
There are only a few situations where I can see them being really useful. As stated before, in sieges, attacking or defending; this should be obvious. The other would be area denial. Say you want to cross a river, but archers on the other side are rudely shooting at you as you attempt to cross. You put your own scorpion/ballista on your side of the river, outrange the enemy archers, and take pot shots at them until they see the wisdom of taking a few steps back, thereby letting your vanguard ford the river more safely.
This is indeed what Alexander did to the Scythians at the Battle of the Jaxartes.
 
  • Like
Reactions: macon
Oct 2018
1,725
Sydney
An instance of an artillery piece used to snipe in a siege and counter-siege context. Zosimus 1.70, describing the siege of the Isaurian brigand Lydius in Cremna, during the reign of Probus:

'[1.70.1] But when he had resolved to persevere against all dangers, there happened at length this accident. There was with him in the town a man who was expert in making engines, and in using them with such dexterity, that when Lydius ordered him to shoot a dart at any of the enemy, he never missed his aim.

[1.70.2] It happened that Lydius had ordered him to hit a particular person, whom either accidently or on purpose he missed, for which he stripped and scourged him severely, and, moreover, threatened him with death. The man was so exasperated on account of the blows he had received, and so affrighted at the menaces, that he took an opportunity to steal out of the town;

[1.70.3] and falling in with some soldiers to whom he gave an account of his actions and sufferings, he shewed them an aperture in the wall, through which Lydius used to inspect all that was done in their camp, and promised them to shoot him as he was looking through it in his usual manner.

[1.70.4] The commander of the expedition on this took the man into favor; who, having planted his engine, and placed some men before him that he might not be discovered by the enemy, took aim at Lydius as he looked through the aperture, and with a dart shot him and gave him a mortal wound.

[1.70.5] He had no sooner received this wound, than he became still more strict with some of his own men. Having enjoined them upon oath never to surrender the place, he expired with much struggling.'
 
  • Like
Reactions: Picard

AlpinLuke

Forum Staff
Oct 2011
27,235
Italy, Lago Maggiore
That seems to be the paper figure, I'd surprised if this actually happened regularly in practice or if even this paper strength persisted for centuries. And, again, is there any evidence for carrobalista besides a single image on a single column? If they were really all that useful and widespread, why do they not appear everywhere in descriptions of battles? I also don't believe in shooting from behind friendly lines. If you consider the depth of a cohort, the multiple lines of cohorts and the gaps between the lines, 100m is not so long. And besides, how would fire control work? The operators wouldn't be able to see what they were aiming at: what happens if you have your own skirimishers in front, or the first line of cohorts pushes forwards more than expected, or your cavalry is flanking the enemy? It's going to take some very robust evidence to deal those major hurdles.

Still, even with these idealised figures, this makes a scorpion about as deadly as, say, a longbowman. Scorpions would have had better armour penetration probably, but I'm not sure how important this is if you can go through most armour already. So the scorpion contingent of a legion would be roughly the same as having 60 medieval longbowman teleported in, but slower to move around and requiring multiple men to use. Useful in some situations, but a drop in the ocean compared to some 4500 heavy infantry.

There are only a few situations where I can see them being really useful. As stated before, in sieges, attacking or defending; this should be obvious. The other would be area denial. Say you want to cross a river, but archers on the other side are rudely shooting at you as you attempt to cross. You put your own scorpion/ballista on your side of the river, outrange the enemy archers, and take pot shots at them until they see the wisdom of taking a few steps back, thereby letting your vanguard ford the river more safely. A variant of this is to force the enemy out of a defensive position. If they are formed up on top of a hill and you want to dislodge them, a frontal assault would be difficult. But you can deploy your artillery in the front rank and start shooting. They can then respond in three different ways. Firstly is to just stand there, and slowly die (this is the worst option); secondly they can retreat from their strong position, thereby granting you your objective. Or, thirdly and most likely, they'll have to leave the hill and close with you, at which point your infantry steps in front of the scorpions and fights as normal. Note that in these cases the scorpions don't have to fire a single shot to be effective, by giving the Romans a wider set of tactical options, they force the enemy to react.

But these are relatively specialised situations. If they were very helpful in standard pitched battles/meeting engagements, then where are the historical texts describing their use in every battle? It's all well and good to theorise, but if there is scant evidence that ballista/scorpions were routinely used to great effect, then they probably weren't routinely used to great effect.
I'm aware of a late treaty about Roman military organization, the "Epitoma rei militaris" by Publius Flavius Vegetius Renatus. In the book II, 25 we see the description of such a weaponry and its usage. Now, the author, who lived between the end of IV century and the beginning of V century CE, [despite he wrote a military treaty] was, with all probability, far from the army. A clue of this is that in his treaty he never makes clear and direct references to the life in a military camp [for a former officer of a legion this would be really odd, so historians tend to exclude that he served and anyway there are no documents proving this]. In some sources he is indicated as "vir illustris" and "comes". This could suggest he was a Senator or anyway in the high class of Rome. "Vir illustris" had introduced when the Senate class became really wide and to differentiate they added that title ["vir clarissimus" was the common title]. "Comes" could indicate that he was in the imperial court as well.
 
  • Like
Reactions: Picard and Olleus
Oct 2011
482
Croatia
That seems to be the paper figure, I'd surprised if this actually happened regularly in practice or if even this paper strength persisted for centuries. And, again, is there any evidence for carrobalista besides a single image on a single column? If they were really all that useful and widespread, why do they not appear everywhere in descriptions of battles? I also don't believe in shooting from behind friendly lines. If you consider the depth of a cohort, the multiple lines of cohorts and the gaps between the lines, 100m is not so long. And besides, how would fire control work? The operators wouldn't be able to see what they were aiming at: what happens if you have your own skirimishers in front, or the first line of cohorts pushes forwards more than expected, or your cavalry is flanking the enemy? It's going to take some very robust evidence to deal those major hurdles.
If memory serves me, Roman legion usually deployed in ranks 6 files deep. Assuming one meter distance between legionaries, that is 6 meters. Even with two meters distance, that is 12 meters. Add some 6 - 12 meters yet again for carrobalista, and you still have 75 - 90 meters useful range.

Still, even with these idealised figures, this makes a scorpion about as deadly as, say, a longbowman. Scorpions would have had better armour penetration probably, but I'm not sure how important this is if you can go through most armour already. So the scorpion contingent of a legion would be roughly the same as having 60 medieval longbowman teleported in, but slower to move around and requiring multiple men to use. Useful in some situations, but a drop in the ocean compared to some 4500 heavy infantry.

There are only a few situations where I can see them being really useful. As stated before, in sieges, attacking or defending; this should be obvious. The other would be area denial. Say you want to cross a river, but archers on the other side are rudely shooting at you as you attempt to cross. You put your own scorpion/ballista on your side of the river, outrange the enemy archers, and take pot shots at them until they see the wisdom of taking a few steps back, thereby letting your vanguard ford the river more safely. A variant of this is to force the enemy out of a defensive position. If they are formed up on top of a hill and you want to dislodge them, a frontal assault would be difficult. But you can deploy your artillery in the front rank and start shooting. They can then respond in three different ways. Firstly is to just stand there, and slowly die (this is the worst option); secondly they can retreat from their strong position, thereby granting you your objective. Or, thirdly and most likely, they'll have to leave the hill and close with you, at which point your infantry steps in front of the scorpions and fights as normal. Note that in these cases the scorpions don't have to fire a single shot to be effective, by giving the Romans a wider set of tactical options, they force the enemy to react.

But these are relatively specialised situations. If they were very helpful in standard pitched battles/meeting engagements, then where are the historical texts describing their use in every battle? It's all well and good to theorise, but if there is scant evidence that ballista/scorpions were routinely used to great effect, then they probably weren't routinely used to great effect.
That, I do agree with. Ballista shooting pots of Greek fire would be more useful, but even that usage I do not recall any references to.

Circa 400 CE, how many cohorts were in a legion? Vegetius says ten, but I thought by that late date the legions had been reorganized to two cohorts per legion. It goes to how reliable Vegetius is.

I do not think that is the case. I had done some research on Diocletianic army some years ago, and it seems that in latter Roman Empire, term legio was used for both actual legions as well as for vexillationes of individual legions. So you could have same legion serving in several places all at once.

While it may well be that legions were reduced in numbers, it is unlikely they were ever reduced to just two cohorts. Two cohorts per legion seems to come from legiones palatinae, but these were just glorified bodyguard, not unlike Praetorian guard or later Varangians.
 

Chlodio

Forum Staff
Aug 2016
4,610
Dispargum
But Diocletian was 100 years before 400 CE. My readings suggest the divided legions eventually became permanent. Two cohorts here, two more over there, two more in a third place stopped being in the same legion and became three separate legions each of two cohorts. Probably long after Diocletian, but by the time of Adrianople, for example. At least one modern history of Adrianople refused to describe the Roman units as legions and instead called them regiments to reflect that none of these units had anywhere near ten cohorts. Admittedly it was a popular history. I don't claim it as authoritative, but I don't think we can compare the legions of Diocletian with the legions of Adrianople or the Notitia.