Here you will learn all you need to know about the Roman Arcuballista crossbow. What it was, how it was likely used and why it was better than a standard bow. You will also see why the Arcuballista was likely a knockoff of the earlier Greek crossbow design.
So, below you have the main takeaway of the entire article.
Arcuballista is a Roman crossbow first mentioned in the military manual named “Epitome Rei Militaris”. It was in use in the late Roman Empire as a handheld device able to shoot projectiles at the enemy with effective distances from 50 to 150 meters.
That is a brief overview. Now let’s go deeper into what it looked like and its capabilities.
The Arcuballista Explained – In Detail

The premise of the Arcuballista is simple. You have a standard composite bow of the era, attached to a wooden stock with a groove etched in. The replica above has a draw length of 40 cm which would mean the bolt would be 50 cm to 55 cm.
The Arcuballista had a rolling nut trigger, to hold the bowstring of the composite bow. So the user drew the bowstring back and attached it to the rolling nut trigger. And the trigger held it in place. Now, a little further back you have the Arcuballistas “butt”. The user could press the “butt” on his stomach and use both of his hands to pull on the bowstring.
We will get into why this was an improvement on the standard bow use of the era a little later on.
Regarding the use of bolt for the Arcuballista. Opinions are divided but it is very likely that they use arrows fir for a bow. It would make sense since the infrastructure for building quality arrows was already in place and if you can just repurpose existing arrows it would make the whole weapon much cheaper to use in battle.
It was cheaper to use the arrows they were already building anyways.
What Was The Effective Range Of An Arcuballista?
We can judge an approximate range of an Arcuballista based on the range of an average composite bow of the era. Which was 50-150 meters.
You can see more details about the average roman composite bow and how it was used by clicking here.
How They Reloaded The Arcuballista
The Arcuballista was reloaded in two ways. You either press the butt of the Arcuballista against your stomach and use both of your hands to pull the string back to the trigger. Preferable way if you are using it on horseback.
The second way is the one used in medieval times and that is to simply place both of your feet on the composite bow and draw the Arcuballista.

The fact that they used both hands to draw the Arcuballista is a perfect segway as to why it was superior in many ways to a standard bow of the era.
Was The Roman Arcuballista Better Than The Roman Bow?
Yes, it was. The Roman Arcuballista was better in many respects when compared to the standard bow of the era when we look from a military point of view.
The bow while extremely effective with draw weights of 80lbs to 90 lbs was an incredible weapon of the era but it had a big drawback. The huge draw weight.
Arcuballista was an effective weapon. But it took a long time to train soldiers to be able to effectively shoot a bow for extended periods of time on the battlefield. So you had to draw the bowstring with 80lbs of force and then hold it in place for a few seconds to aim and then you release.
Then you repeat the process again and again.
That takes a lot of muscle mass. Which takes time to build. So the Arcuballista was an effective way to bypass that. The user of the Arcuballista used both of his hands to draw the Arcuballista. Which was a lot easier than using just one hand. Even when you draw it you attach the string behind the trigger.
So, the trigger is holding the pressure of the composite bow with 80 lbs of draw weight. Not your muscles. So if you are a skinny weakling like me, firing an Arcuballista is no problem, whilst firing an 80lbs compound bow is a problem.
The Roman Arcuballista was better than the bow because it shortened the time it took to train an average citizen to become an effective soldier.
Added Benefit For The Romans
By employing the Arcuballista the Romans had a quicker way to train cavalry with ranged weapons. Without the long training times, it took the Huns to become masters at mounted archery.
The only drawback is that a well-trained archer had a faster firing rate than a well-trained user of an Arcuballista.
How We First Discovered Arcuballista Were Used?
There are a couple of written accounts mentioning a handheld crossbow used by the Romans. One of them comes from a Roman historian Vegetius. In his military manual “Epitome Rei Militaris” he says:
The besieged normally defend themselves against these contrivances
Epitome Rei Militaris by Vegetius, Book IV Ch. 22
using catapults, mangonels, “scorpions”, crossbows, “sling-staves” and
slings.
He lists Scorpions and crossbows separately which would indicate they were two different weapons. The other piece of evidence comes from a stone relief from Roman Gaul.

Here we can clearly see the outline of an Arcuballista and a quiver. Likely used for hunting.
The other indication comes from a cavalry commander Arrian in his book “Tactica”. There he describes cavalry units firing a handheld type of crossbow. Arcuballista fits the description here.
Why The Arcuballista Was Likely A “Rip-Off” Of An Earlier Greek Design
This comes as no surprise to any history buffs reading this. The Romans were quick learners so when they saw something they liked they quickly copied and improved upon it.
Arcuballista is likely one of these things they copied. The Ancient Greeks adopted a similar crossbow design to the Arcuballista many centuries before it was introduced in the Roman Empire. It was called the “Gastraphetes” or the belly shooter.
Let’s see the side-by-side comparison:

They even draw the crossbow in a similar way.
The Romans improved upon the design by making it smaller.
In Conclusion
Thank you for taking the time to take a stroll down memory lane on the history of this particular type of ancient crossbow.
If you want to take a look at an article I did on the detailed history of Crossbows then go here.
And click here if you want to see what arrowheads were made of throughout history.
Take care