Throughout this little project I have had conversations with people from various camps of interest.  It started out back in the day when Firefly was just a pup.  Many hunters who saw her seemed concerned with whether that “thing” could kill a deer.  Or equally, “Why don’t you put some wheels on the limbs and make it into a compound bow, because, you know, the Romans  had wheels and everything.”

…Well okay then…    Perhaps they all went to sleep the moment I uttered the words “history project”.  However, these folks were generally kind and I tried not to let their suggestions bother me overmuch.

Most of the pestiferous comments  came from reenactors.  One chap took exception to the style of washers that appear on Firefly.  (“Modioli” to the truly erudite.)   Clearly they are not typical of anything that has been dug up.  They were made that way to increase the stability of the crossbars during certain spring tensioning experiments.  With Phoenix the historical shortcomings of Firefly’s washers will be addressed with more authentic full collar versions.  Rome wasn’t built in a day, nor are effective reconstructions of her torsion artillery.

If you are a reenactor and reading this blog with your eagle eye ready to pounce on something that can be shown as “inauthentic”, here are a few caveats to help guide you in your criticism.

(1)   Whatever you are thinking of criticising, it is very likely I have agonized over it to a certain degree.  While I am fully committed to the idea of ultimately achieving parsimony in the designs that are pursued in these reconstructions, I do not consider myself a slave to it during the development process.  This is because a large part of my work is to conduct experiments to see what made these machines function  as effectively as the record suggests.  At times these experiments may require adding components that, in all likelihood, would not have been seen on the originals.  Like the doppler chronograph hanging on the front of Firefly, or the Vernier plates   counter washers that are used to produce finely grained rotational adjustments for the washers.  Eventually I hope to be able to remove any complexities that were added for testing purposes.

Take this design for a cable backed limb.  It proved successful after nine previous attempts did not.  Some of the draw weights I was experimenting with topped 5500 lbs.  A couple of limbs outright broke.  Albeit without much fanfare thanks to a Kevlar safety strap.

cable limb

Certain highly engaged fellows have suggested that this type of limb is not at all “authentic”.   …..Epoxy soaked Dacron yacht braid not authentic?  Who’d have thought? However, as a stepping stone to a more historically correct steel tension rod, this way of going about limb development has many advantages for the tests we are doing.  Little things like safety come to mind. Or selecting the size and grade of steel rod, now knowing 11,000 lb. test yacht braid is sufficient to back the limb.  Or developing the attachment techniques to anchor an advanced version of Kevlar safety strap down the relatively stress-free  middle of the limb.

My approach is to first develop authentic performance within as plausible a platform as possible, take note of those places where authenticity in the build may have been breached, and then do the reworks needed to bring questionable areas more into historical compliance, all without harming the performance overmuch   (Notice I said “more into historical compliance”, there are no absolutes of perfection possible here.)  The safety strap will always be with us though, and the authenticity police will just have to lump it.

I do not believe I have ever suggested that our work here was geared towards making a “perfect” show-and-tell replica of how these machines must have appeared.  No one really knows, nor will they unless a complete specimen is found.  Even then, there were in all likelihood any number of variations on the basic design.  Iron frame ballistas appear to have spanned at least three centuries, perhaps more.  Variations are inevitable. The unknowns are vast.  Similarly, using Heron’s description of a small Cherioballista to validate interpretations of much larger machines, like the Orsova, is fairly presumptuous.  There are just too many imponderables for narrow windows of textual evidence of this sort to be relied upon.  Soft evidence vs. hard evidence?  Clearly I favor the latter, and even then I’m quite happy to admit I’ve probably got parts of it wrong.  It’s just the nature of the beast.

This is an experimental game we are playing, based strictly on replicas of certain artifacts,  just like the name of the discipline suggests.  Inevitably anyone working in experimental archeology will mix and match the evidence to suit their particular viewpoint.  I admit to this tendency myself, with perhaps one important difference.  For me, performance is the great common denominator. It is also the one key area where EA has failed to show any great insights into how these machines probably worked. Unless you consider all the negative attempts that show what doesn’t work.  There are plenty of them around.  Large parts of my own project are filled with such failures.

And so, when it comes to experimenting with catapults, for me the bottom line is all about performance.  Otherwise, what is it you have built? You might as well have made a nice drawing or computer graphic to illustrate your point.  High energy catapults are not for everyone.  There is always risk in such endeavors and it is best to be realistic about your capabilities.  For those of us working on the extreme sport aspect of these machines, the dangers to life and limb are very real.  Which, of course, is part of the appeal. So in short, there are substantial differences between  catapults built for educational and display purposes and those few machines that concentrate on shooting projectiles with authentic levels of power and range.  There is certainly nothing wrong with the former.  Let’s just not confuse the two.

That being said, appearances are important.  On one level we are creating a test bed for experimentation, and on another we are attempting an artistic creation.  Without this latter, the project would be a flat and soulless entity, and I make no apology for any authentic sensibilities that are offended by the aesthetics of what I am building.  For example, I like the curvy bits on Firefly’s stock profile.  They should be easily contained inside any reasonable parameter of how these machines may have looked.  After all, no one really knows do they?  If you are a rectilinearist and the curvy bits don’t work for you, so be it.  Think of them as a reminder of the enormity of what we don’t actually know about these machines.  The closed mind seems strong only to it’s occupant.

(2)  At times our work will show designs that may, at first glance,  seem needlessly complex.  If they are not the result of the aforementioned experimental aspects, they may be a form of thematic extension played out from well founded features that are apparent in the artifacts.  For example, it is indisputable that all the kambestrions that have been found (other than one that was mis-cast)  are equipped with four loops attached to their upright stanchions.  These loops are a clear indication that the machines were able to be disassembled with a minimum of fuss (i.e. they are modular, take-aparts).

If we respect this modular premise properly, it doesn’t make much sense to have only the kamarion and kambestrion be equipped with a take apart feature, when clearly other parts of the machine would also need a take-apart feature to make this design strategy a practical benefit.  Ergo, other parts of our reconstruction should follow suit and be easy to disassemble.  Now, does this mean we are over-engineering?  Not so much, by my reckoning.  Not if there are good reasons to include them.  It is just a matter of honoring the intent apparent in the artifacts themselves.

(3)  A couple of actual catapult scholars have suggested that if modern reconstructions are not equipped with sinew springs, then pretty much, the whole exercise is worthless as we will never know how the originals performed.    I consider this a fairly shallow objection.   It is true in a certain absolutist way, but fairly uncomprehending of what it takes to get these mechanisms working at a high level.  For example, take the subject of shooting accuracy.  There is no reason to suppose that the ancients would not have made high quality sinew springs that were, at least when dry, stable and reliable power generators.  This is not strictly provable as yet, but is a pretty sure bet for those of us that have actually worked successfully with nylon spring cord and dabbled with sinew a bit.  And so, if we can suspend our disbelief for a moment, and take as a given that Roman springs, however they were made, were up to the task of consistently powering their machines, we might well ask, “what other myriad factors are there in making a ballista shoot accurately?”.  And this, of course, is something we can test for very well.

(4)  I could go on, but let me just conclude with this: if you feel an objection rising in your throat, please make sure you understand where this project is coming from.  While  performance founded on parsimony is our ultimate goal, we have to be pragmatic about it.  So to repeat myself: I believe it is more productive to utilize the minimum innovation necessary to generate authentic performance, and then after thorough testing, come back with reworks to make everything as historically plausible as possible without losing all that hard won performance.  Your concerns over “authenticity” will be addressed eventually. The quickest way between two points is not always a straight line.

This behemoth of a machine is without a doubt the king of all minimally-working, display ballistas.

bbc ballista 3

It was made for the BBC program “Building the impossible”.  The scholarship that directed the project is generally considered as impeccable, and clearly the effort was very well funded. As I recall the range was  about 120 yards, and only a few shots were managed before it became irreparable.

I do not doubt there was a certain amount of dissatisfaction with that range of shot and longevity of the machine.  Trying to balance authenticity in the build with authenticity in the performance is what makes this game tick.  I truly wish them better luck with their next endeavor.

Progress with catapult reconstructions is a process, not an event.  But try telling that to a TV producer.  Or, for that matter, a scholar trying to illustrate their pet interpretation of how these machines “must” have appeared.

Put another way, comes this email from fellow catapult maker and teacher from NZ,  Murray Hill:



With all that said, I would like to extend my thanks to Murray and the other reenactors and scholars that have appreciated what I am attempting to accomplish with these reconstructions and experiments.   I prefer not to mention names more than necessary, but you know who you are.

Back to my experiments now…


And here’s a plug for Murray’s book —


Codex catapulte


Murray brings enough humor to the subject of ancient catapults, I found it hard to tell the difference between laughing and learning. Definitely not for catapult prudes or folks that can’t stand a good belly laugh mixed in with their scholarship. Just my cup of tea.



And because this next book provided me with the inspirational backbone to keep going when the appeal of ancient torsion tech was at it’s lowest ebb, I highly recommend this modern classic by Dr. Tracey Rihll from Swansee University.  Consume this over a long weekend and you will have a firm grasp on the history of catapults, what they were likely capable of, and how they affected the ancient world.  Not many stones left unturned here.  A dedicated work of scholarship, kept lively by the prudent use of imagination to help guide the reader into an appreciation of how vast are all the things we do not know about ancient technology.  Not a snoozer like some.

Tracey Rihll



This little book by Duncan Campbell is a good primer on ancient catapults.   The author keeps a tight reign on any speculation regarding catapult theory and effectiveness.  Although, it must be said, some of the illustrations depict machines with idealized versions of resting torsion springs, all very straight and ticketyboo.  However, the book is well thought out in it’s presentation of the basic facts.  It was my first introduction to the Orsova artifacts and it’s photos are what spurred me to undertake the Firefly project.  I always keep it handy for quick reference.

Duncan Campbell



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