Whenever Roman battles are portrayed in movies they usually have one thing in common. The mortality rate of the soldiers is ridiculously high so that the battle ends with most participants dead.
But that is not an accurate depiction of reality! So let`s look at the real mortality rate of Roman soldiers and how many Roman soldiers actually survived their service until retirement.
Numbers given by the Roman writer Livy indicate an average mortality rate of 8.8%. A Roman victory did on average cost the lives of 4.2% of the participating Roman soldiers. That number rose to 16% in case of a defeat. Between the years 200 and 168 BC, the chance of surviving the mandatory 12 years of being eligible for military service was 34-40 %.
Let`s take a closer look!
The Mortality Rate of Roman soldiers during the Roman Republic
One major disclaimer up front. The actual mortality rate of Roman soldiers throughout the Roman Republic and the Roman Empire is unknown. There are however a couple of periods in time where we have a pretty good idea of the mortality rate of Roman soldiers.
One of these periods where the data is pretty good is the time of the Middle Republic, a time in which Rome expands its supremacy over Italy to the Mediterranean. During that time, 272-146 BC, the Roman military was also extremely different from what we usually think of. But that is a story for another time, here you can find out more about the three lines of battle (the Hastati, the Principes, and the Triarii) that made up the Roman Legions during the time of the Punic Wars.
One of the major sources regarding the mortality rate of Roman soldiers during the Middle Republic is the Roman writer Livy (59 BC-17 AD) who not only wrote about the origins of Rome but also included lists of legions, battles, and casualties in his work. His numbers put the average Roman casualty rate at 8.8 %.
However, two problems make the combat mortality rate of 8.8 % seem at least questionable. The first, more general problem, is that Livy lived more than a hundred years after the Middle Republic. So he did not write down first-hand knowledge. The other problem that is much more important when talking about the mortality rate of Roman soldiers in battle is that Livy lists a disproportionate amount of Roman defeats.
And Roman defeats were always more costly than Roman victories.
That by the way is also true for ancient Greek warfare. Here you can find out more about how high the mortality rate of Greek Hoplites was and how (if at all) it differed from the mortality rate of Roman soldiers.
An average of 4.2 % of engaged Roman soldiers died in a battle in case of a Roman victory. But the number rose to 16% in case of a Roman defeat. So when the numbers that Livy lists are disproportionally Roman defeats then that distorts the results. So we can assume that considering a mortality rate of on average 4.2% in a victorious battle and 16% in a lost battle the average casualty rate of Roman soldiers might have been a little under 8.8%.
But how exact are the casualty numbers that Livy gives us? Wouldn`t Roman generals try to manipulate the numbers?
Did Roman armies count their fallen & how accurate are these numbers?
It seems like whenever possible a Roman army would count its fallen by actually counting the corpses on the battlefield. But there were some instances – like defeats – when that was not possible.
In case counting the corpses after a battle was not possible each Roman unit subtracted the number of missing men from its original strength and passed that number on to the responsible officers. The downside of that method was that fallen soldiers were counted together with captured and deserted soldiers.
And while that procedure makes it impossible for us to find an accurate mortality rate it was sufficient for the Roman army. It did not make a difference for the main purpose that the Roman army needed the number of fallen soldiers for whether a soldier had fallen or been captured.
The reason why the number of fallen (or better said missing) soldiers after a battle had to be determined did mainly have to do with logistics. Feeding a Roman army took a lot of planning. Only 100 Roman soldiers would need 3 tons of wheat every month. And that does not include the additional types of food these men needed on a regular basis.
Here you can find out more about the diet of the Roman soldiers.
Apart from being needed for logistical reasons the number of fallen soldiers was also frequently reported to the Senate in Rome.
And while low casualties were probably not mandatory for being granted a triumph, something each Roman general wanted for multiple reasons, an extremely high casualty rate did certainly not bring any sort of positive recognition within the Senate.
The Senate, more precisely the men within the Senate, was also the reason why most Roman generals were not successful in deceiving the Senate over their true casualties.
Roman senators were politicians who all had military experience (military service was mandatory for any sort of political career in Rome) so they had a pretty good understanding of casualty rates and knew when a general tried to make his casualty rates appear lower than they actually were.
Here you can find out more about the political system of the Roman Republic, its institutions, and what sort of military service was crucial for starting (and advancing in) a political career.
Ok, so during the Middle Republic the average mortality rate of a Roman soldier was probably a little under 8.8 % (4.2 % in case of a victory and 16 % in case of a defeat).
But how did that number change during the time of the Roman Empire?
The Mortality Rate of Roman soldiers during the Roman Empire
During the Roman Empire, the Roman military looked a lot different from its counterpart during the Middle Republic.
Not only had the differentiation of infantrymen into Hastati, Principes, and Triarii (each with different equipment and responsibilities, more on that here already been dropped during the Late Republic in 107 BC. During the time of the Roman Empire, the Roman armies were also no longer raised for individual campaigns but were standing armies stationed in border provinces.
Here you can find out more about that development.
That deployment in border provinces meant that now the Roman army was not raised for war but was permanently stationed in the provinces.
As a result, some Legions were stationed in extremely peaceful provinces (like on the Iberian Peninsula) so that some soldiers could spend their entire length of service without ever fighting in a battle. Other, less lucky recruits could be sent to a legion that stood at a highly endangered border (like the Limes, the border between the Roman provinces and the Germanic territory Rome had not been able to conquer).
By the way, here you can find out more about the recruitment of Roman soldiers, how many recruits were needed each year, and how recruits were trained and distributed among the existing Legions.
That difference between Legions stationed in peaceful provinces and those stationed at disputed borders did not only create tension between the Legions but also makes it difficult to come up with an average mortality rate of Roman soldiers during the Time of the Roman Empire.
It seems like the average mortality rate of Roman soldiers of the Middle Republic (4.2% in case of a victory and 16% in case of a defeat) might also be accurate for the time of the Roman Empire.
But what does that mean for the chances of a Roman soldier to survive his military career?
What percent of Roman soldiers survived their military service?
When we look at how many Roman soldiers actually lived long enough to make it to retirement, more on the retirement of Roman soldiers in my article here, we once again have to differentiate between different periods of Roman history.
Since I wrote most of this article about the mortality rate of Roman soldiers during the time of the Middle Republic I think it makes sense to also look at that period when talking about how many soldiers survived their military career. During that time period, the Roman military didn`t consist of soldiers who enlisted for 20 years but of citizens who were wealthy enough to provide their own equipment. Here you can find out more about that system and how it eventually destroyed the Roman middle class.
Each man meeting the requirements could be requested to participate in a war for 12 years. Between the years 200 and 168 BC, the chance of surviving the mandatory 12 years of being eligible for military service was 34-40 %.
So now we have looked at the mortality rate of Roman soldiers. But it might also be interesting to pair that up with a brief look at the casualty rates that the army of one of Rome’s most serious threats – Hannibal – suffered in the battle of Cannae.
The Casualty Rate of Hannibal’s army at the Battle of Cannae (H2)
The battle of Cannae was one of the most severe Roman defeats of all time. But not only Rome did have high casualties.
Hannibal lost around 5,700 men (11% of his army) at the Battle of Cannae in 216 BC when he inflicted a crushing defeat on Rome. And his very successful ambush at Lake Trasimene did cost him another 1,500 men (3% of his army).
The difference was that, unlike Rome, Hannibal could not fully replace his losses which eventually led him to lose to Rome. That ability to just replace lost armies with the almost inexhaustible reservoir of recruits that Rome controlled was actually one of the major reasons for the success of the Roman army.
But the reasons for the success of the Roman army are a story for another time. If you are interested in these reasons then I would like to recommend you my article here.
Take care of yourself because you deserve it. You really do.
Until next time
Johannes Kromayer: Heerwesen und Kriegsführung der Griechen und Römer (München 1963).
Nathan Rosenstein: Rome at War. Farms, Families, and Death in the Middle Republic (Chapel Hill 2004).