Roman Artillery

[First_Legionary]

I can't seem to find any reliable sources on Roman Ballistas or even their artillery in general (I posted this question in another forum on this site but it received no comments). What I need to know is how large Roman Ballistas became, what year they were first being made, the weight and size of the ammunition fired by the larger and normal sized ballistas, and if the larger ones could have or were used to take down the walls of a fort or city. Sources and links are greatly appreciated.

[arklore70]

Dustin,
I would start with Osprey publishing. If I am not mistake they seem to have a book on the subject.

Peter Connelly has a bokk also titled sometlike Greece and Rome at War.

If you Go to the Legio VI Victrix website as well as Jared Fleury's web site, you can see one in action.

While this may not directly answer your question, hopefully it leads you to them.

V/r
Mike

[Emeraldweapon7d]

this is the site that got me started in seige artillery, lots of cool stuff.
http://198.144.2.125/Roman/Roman.htm

[aitor iriarte]

The Osprey book by Duncan Campbell (Highly commendable):
CAMPBELL, D.B. & DELF, B. (2003): Greek and Roman Artillery 399 BC – AD 363. New Van-guard 89. Osprey Publishing.
Both Philon and Vitruvius (10.11.3) give lists of ballistae sizes. That of Vitruvius seems to be rather messed or corrupt and that by Philon (Bel. 51.20-26) ranges from 10 minae to 3 talents (sizes down to 2 minae are also attested) 1 mina = 436.6 grammes or 0.96 lb. There are 60 minae in one talent.
It is usually assumed that ballistae were only useful to knock down upper structures and battlements but Philon (Par. 80.45 commends to construct city walls thicker than 10 cubits (4.62 metres or 15 feet) to resist stone throwers.

Aitor

[D B Campbell]

... and don't forget Alan Wilkins' Roman Artillery (Shire: Princes Risborough, 2003).
Alan was the brains behind the BBC ballista (but was over-ruled on certain key issues, which ultimately caused the machine to fail). He is now working on a smaller example based on Vitruvius' text.

That of Vitruvius seems to be rather messed or corrupt ...

As far as I remember, Alan follows Marsden's belief that Vitruvius' figures (for spring size versus missile weight) are corrupt. However, I believe that they are correct, and demonstrate the superiority of the Roman ballista over the Hellenistic lithobolos described by Philon.

Philon (Par. 80.45) commends to construct city walls thicker than 10 cubits (4.62 metres or 15 feet) to resist stone throwers.

This passage is problematic. I don't have Garlan's commentary to hand, but I remember the figure of 3 cubits also occurs.
Do you have the precise text there, Aitor?

[aitor iriarte]

Hi Duncan,
No, sorry, I haven't got it As you know, I'm alwayhs looking for a good edited, commented and (English) translated text of Philon's Poliorketika and Paraskeuastika. I was quoting from Marsden.
Therefore, you think that Vitruvius ballistae achieved the same result with less spring diameter? I cannot say that it isn't correct but everything turns doubtful with Vitruvius' numerals (And some people says that Philon's ones are corrupt too hock: Then we'd have no measurements at all...)
The problem with Alan is that he thinks beforehand that some (or many) things are impossible and that is totally unscientific! :wink:

Aitor

[CYL]

May I suggest the bibliography at the bottom of the Wikipedia article.

Normally, I wouldn't suggest Wiki, but since I put it in and it comes from my undergraduate dissertation from last year, it's a good starter point. :wink:

Especially the Shire Archaeology book, it's very good indeed.

I think you can get them all off Amazon.

[Eleatic Guest]

Normally, I wouldn't suggest Wiki, but since I put it in and it comes from my undergraduate dissertation from last year, it's a good starter point. :wink:

Hello. Have you sources respectively evidence for your following two remarks?

It is considered to be the most complex weapon made before the Industrial Revolution and the only pre-industrial weapon to be designed scientifically.

...a universal joint (which was invented just for this function)...

Could you send me by chance your dissertation. I am genuinly interested.

[CYL]

That wasn't my bits. Sorry.

I reformatted, rewrote and added a lot of it, but not those bits. Sorry.

I'm an archaeologist, I would never say anything as quantative as:

It is considered to be the most complex weapon made before the Industrial Revolution and the only pre-industrial weapon to be designed scientifically.

or as open as:

At some point, ...

I did say that there was a swivelly thing (though not in those exact words, obviously), but I suppose someone must have re-written it.

It's the joy and weakness of Wiki, unfortunately.

I only put information up there if I know it's been historically/archaeologically verified. I tried to make it as academic as possible, so I referenced it as much as possible, and only put in places that had dates or recorded names attatched.

[D B Campbell]

It's the joy and weakness of Wiki, unfortunately.

I have previously championed the cause of Wikipedia (elsewhere in this forum) as being a wonderful idea, but I'd be the first to admit that the reality often falls far short.

This would appear to be a case in point (and, as an AOL user, I am powerless to correct Wikipedia).

The Greeks never used the term ballista to describe their stone-projecting catapult, so the section on "The Ancient Greek Weapon" is misplaced. Really, to be accurate, this article should confine itself to Roman weapons.

The section on "The Roman Weapon" implies that the machine only came to Roman notice after 146 BC, whereas requisitioned weapons (presumably Syracusan) and captured Carthaginian weapons had been employed by Roman armies during the Punic Wars.

There are many doubtful and misleading ideas in the Wikipedia article. Here is a sample paragraph:

The ballista was a highly accurate weapon (there many accounts right from its early history of single soldiers being picked off by the operators), but some design aspects meant it could compromise its accuracy for range. The lightweight bolts could not gain the high momentum of the stones over the same distance as those thrown by the later onagers, trebuchets, or mangonels; these could be as heavy as 200-300 pounds (90-135 kg).

Accuracy of the ballista: We can certainly assume that these weapons were accurate. Reconstructions of the arrow-shooting catapulta (scorpio) have frequently demonstrated amazing accuracy, but there are no comparable data (afaik) for the stone-projecting ballista.
The statement that "there many accounts right from its early history of single soldiers being picked off by the operators" is false.

Range of the ballista: I am not sure what the writer means by "some design aspects meant it could compromise its accuracy for range". What design aspects?
I could hazard a guess that the writer perhaps has in mind the false notion that the ballista operated like a mortar, lobbing missiles blindly (in the absence of spotters and modern electronic aids).
All of our (limited) evidence suggests that the ballista shot its missiles over a low trajectory in order to achieve maximum impact.
Dietwulf Baatz has an entire paper on the subject, illustrated by a splendid diagram (which I borrowed for my Greek and Roman Artillery, p. 21).

And the statement about momentum is just bad physics. Missiles do not gather momentum. Their initial velocity is gradually eroded by air resistance, which has a greater effect on the large, sub-spherical ballista ball than on the sleek, aerodynamic catapulta arrow.

Most of the many errors derive from the writer's confusion between ballista and artillery in general, as well as unfamiliarity with Roman military practice.
I would probably excise Connolly, Feugère, and Goldsworthy from the Bibliography as they are not strictly relevant. I would definitely add Marsden 1969 and Baatz 1966, 1971, 1977, 1978, 1980, 1982, 1983, 1985, ...

[Eleatic Guest]

Hello,

I have two questions after further enlighten me with Osprey:

1. Did Roman torsion artillery recoil or not? Did operating torsion artillery on towers damage the building? What are the physica here?

2. How did Roman artillerymen vary range, especially with the Onager? I mean, they could not just move the cushion, since it was pretty much fixed, and would take a day or two to put it into another position vis-a-vis the throwarm.

[conon394]

The twine armed torsion devices do not seem to have transferred any significant recoil to the structures they rested on (they seem to have no adverse affect on the mobile and/or wooden ship based platforms and towers the Hellenistic world liked to use).

You might ask D B Campbell directly on you first point he has at least one article in Britannia (‘Ballistria’ if the First to Mid-Third Century Britain: A Reappraisalâ€

[Eleatic Guest]

http://www.rubensaez.com/descargas.htm

Many good articles on Roman and Greek siege warfare with timelines of introduction of various methods at the bottom of some pdfs.


Conon394,

I am going to look for the article, thanks. Actually my questions were inspired from reading his Osprey book on Roman artillery. :wink:

[D B Campbell]

1. Did Roman torsion artillery recoil or not? Did operating torsion artillery on towers damage the building? What are the physica here?

Basically, the weight difference between the missile and the machine cancels out any possible recoil. The re-enactment societies that practice with catapults will be able to confirm this, simply by empirical observation.

I used the example of a light arrow-shooter in the Britannia article that you referred to. I assumed that the arrow weighed around 120g, and was shot from a machine like the Ampurias catapult, weighing around 60kg. (This is where I got the ratio of 1:500, mentioned on p. 80 n. 40.) I don't actually have a catapult, so it would be nice if some of our catapult-owning friends could fine-tune these data.

If the arrow is shot at around 50m/s (a reasonable conjecture -- I believe Alan Wilkins has clocked his scorpio at about 60m/s), the arrow has an initial velocity of 6kg*m/s (= 120g x 50m/s). It is a law of physics that the same impulse is transferred into the catapult, where it is absorbed by the heavy wooden framework (6kg*m/s divided into 60kg = 0.1m/s). Translated into energy, this is 1/2 mVV, or 0.3 Joules -- in other words, "not very much". (This is the "less than 1 joule" that I mentioned on p. 80 n. 40.)

My mentor and colleague Dietwulf Baatz once put this into context for me by comparing it with a 2cm machine gun! The 120g bullet (same weight as the ancient missile) is fired at 1000m/s (much faster than the ancient missile), giving an initial velocity of around 170kg*m/s (including an estimate for the explosive gases). Again, the same impulse must be transferred back into the weapon, in this case an 8kg machine gun (much lighter than the ancient catapult). This time, the 170kg*m/s divided into 8kg gives an impulse of about 21m/s, which can be translated into a "kick" of around 1760 Joules. This is 6000 times more than the ancient weapon produces!

2. How did Roman artillerymen vary range...?

Here, you are begging the question, Stefan: would the ancient artilleryman want to vary range? I believe that this was a minor consideration. Dietwulf Baatz has been a proponent of short- to medium-range direct shooting, over a reasonably flat trajectory, in order to maximise the damage and make targeting easier. I think this makes sense.

I disagree with Eric Marsden's theory, that catapults were shot over a more or less steep trajectory, like a modern mortar. In my opinion, this makes no sense militarily, and creates all sorts of problems for the artilleryman.

On the contrary, shooting over a flat (or flattish) trajectory means that objects are either already within range, or not yet in range (but soon will be!) -- there is no other alternative.

2. ..., especially with the Onager? I mean, they could not just move the cushion, since it was pretty much fixed, and would take a day or two to put it into another position vis-a-vis the throwarm.

This is an interesting point, because the onager appears to lob the missile, rather than shooting directly (like all other catapults).
However, Michael Lewis has demonstrated mathematically that the trajectory can be altered by adjusting the angle of the pin at the end of the throwing arm, and by adjusting the length of the sling.
Of course, we don't know whether the ancient artillerymen actually did this. Lewis has simply shown that it could have been done this way. So the onager could deliver its missile over a reasonably flat trajectory, too, with the benefits of maximising damage etc.

(Apologies for such a lengthy post. I hope it makes some kind of sense. :wink: )