[Lafayette C Curtis]

How much evidence (if any) do we have for the actual use of onager-type catapults (i.e. with a single throwing arm operating in the vertical plane, powered either by the tension of bending wood or the torsion of twisted ropes at the base of the throwing arm) in medieval Europe? I keep seeing them in movies and popular culture representations but so far I've had no luck locating primary information on actual medieval onagers (the catapult, not the ass), so I'm wondering if there's somebody around who might know a bit more about the matter.

[Tim Ormsby]

Well I can't actually say that I know more about the matter, but I just picked up a copy of "Arms through the Ages" by William Reid (30 bucks...so worth it). I read that once gravity powered engines (i.e. trebuchets) were introduced, torsion powered catapults weren't as widely used because of the climate. The higher rainfall and generally wetter conditions in Europe made torsion engines less useful because moisture makes the torsion fibres lose resilience, making the catapult useless.

[Kurt Houghton]

yeah, that is true, the onager was more a greek and roman weapon, along with the ballista and a mix between both !!! but like before, the wetness of the rope meaning the uselessness of it all

[Randall Moffett]

There was an article in the Royal Armouries Journal in 2006 I think, Spring on this. It basically said there was no evidence for it... that said I know of at least three drawings of them from the 13th and 14th so I think it unlikely they did not exist. The Walter de Milimete manual with the gun also includes a picture of one of these torsion powered machines. How common they were is anyones guess as the text evidence usually does not give enough info to really know for sure.

Medieval non-gunpowder artillery is one area that really needs a good bit or modern research as what we have is usually based on very old research and the new stuff is not on a very large scale. Seems firearms has sucked most of this time up...

RPM

[Craig Peters]

[Randall Moffett]

Craig,

This has become more and more common of a viewpoint the last decade or two, though as I stated earlier suffers from either lack of familiarity with some sources or ignoring them. I hardly would call clear representations in artwork no good evidence. Milimete's drawing is irrefutably a torsion catapult. The R.A. article spent the entire time going all over artwork that was little known but missed one of the best know military texts of the 14th.... It has been a long time since I read the Latin siege warfare so I could not say but remember I felt about the same regarding its evidence and conclusion.

That said I do figure traction based engines were much more common than suspected commonly. That said there must have been a huge amount of types of engines for war we have no idea about by the huge number of different ones in inventories.

RPM

[Gabriele A. Pini]

The Osprey's ebook "Medieval Siege Warfare" (Elite 28) in comment to the plate H1 talk of a manuscript of the 15th century that rapresent an onager, and I don't think it was the Milemete's, because it is pictured at page 29. Probably the onager fell out of favour for various motives (not last the more difficult service of the ropes, as we can testify) just before the drawings of the great manuscripts (13th century onward), especially if, as someone supposed, the trebuchets arrived in Europe from China (the traction trebuchet, o "petraria") with the crusades (Scientific American - july 1995 - Paul E. Chevedden - The Trebuchet)www.deremilitari.org/resources/pdfs/trebuchet.pdf

Side topic: Someone know anything about the ropes of a onager? We have attempted with hemp ropes (I don't know the exact english term, but I assured you it was the italian hemp), even going as far as to flax-oiling them with a 3-day bath and then a one week drying... With the result that, after only 3 launch, the ropes gone to hell (without the oil, it resisted 2 launch). Now we use nylon ropes (I know, I know, I flagelled myself every night) but I would like to know the medieval soultion (even only to explain the reality to the people who see our onager)[/url]

[Jean Thibodeau]

I could be completely wrong and I don't remember the source but wasn't horse hair used to make the ropes for a tortion type siege engine by the Romans ?

[Randall Moffett]

Jean,

Sounds about right. London used it for balistas as well.

RPM

[Craig Peters]

[Randall Moffett]

In fact I do. It, sadly, is only a line drawing.

It is possible it came back after the Roman era. I think it would be a hard push though since the eastern half remained and continued much of their old military tech. To be fair I would need to get back inot early and high medieval research to get more familiar with the evidence there. All I can say for certain is that there is clear evidence in artwork depicting such engines. The fact that torsion 'springalds', 'balistas' and the likes are in use during at the least the late 12th shows that torsion power was still a used tech for war, so I do not see onagers to be far out of the question at this period.

RPM

[J.T. Aliaga]

I was flipping through Nossov's Ancient and Medieval Siege Weapons yesterday at the book store. He has several arguments against medieval onagers.
-He states there are no post-Roman representations (I assume he means pictures) of onagers until the 14th century.
-Most of these are also slingless, showing a spoon holding the projectile(s). Some are clearly the creation of a overly-imaginative artist.
--The representations often show wheeled onagers. These would be mechanically unsound and would likely self-destruct if actually fired.
-The 14th century is also about the time we seen cannons becoming the primary artillery weapon; Nossov argues this is an indication the interest in torsion powered weapons is less practical than theoretical.
-Nossov uses al-Taursi's text (12th cen) as evidence only 1 tension artillery weapon (the ziyar) is commonly used. All others mentioned are beam-sling and man- or counterweight-powered.

Nossov had some other arguments. I tried using Google Books for reference but it's currently blocking the relevant pages.

[Randall Moffett]

Aliaga,

Nossov's book sounds interesting. His argument against onagers seems rather weak to me though. How does he prove it is an over active imagination of the artist? So he states there are no pictures as evidence by getting rid of those he does not like with a flimsy statement like that..... sounds fairly feeble to me. There are too many such illustrations from a wide number of places and times to write them off so summarily without anymore of an argument than that.

Several largish spoon type catapults have been made modernly and seem to work fairly well so not sure that argument holds water either. Not as effective as sling types true but writing them off as fantasy because they are not as effective would disregard all sorts of things in actual use in the medieval period.

Cannon were not the primary engine of siege warfare in the 14th, not even in the end of the period. Anyone selling that line must be very unfamiliar with primary sources. Clearly their use increases but it goes from 0 to a small number mid century so it has no where else to go but up or discontinue. At the very end of the century the bombard begins its run to become so but most current arguments on firearms put the change to primary use of cannons into the 1430s, 1420s at the earliest. I think Cliff Rogers covers that in his artillery revolution fairly well and Bert Hall more or less agrees perhaps having it a bit later.

We know they used torsion technology in medieval Europe for siege engines. Loads of horse hair was used in German, French, Italian and English towns for engines and springalds and such, so the concept is clear in real application. If it is there in artwork I cannot see why it would be classified as fantasy. My only thought rests on it being supplanted by things like the trebuchet and later firearms but even so it’d be unlikely to have been done quickly or even completely. .

RPM