Size of Hannibal's Army Ebro-Po

Duke Valentino

Ad Honorem
Jul 2017
2,367
Australia
As discussed before, Cannae has 2 separate battles, Rom left behind 2 legions to guard their camp, forcing Hannibal too to leave behind a force to protect his own camp. So the 80,000 starts off with only 70,000, 50k infantry and 20k skirmishers.

And I don't think it is impossible to field 50,000 heavy infantry in a mile. Let's say it's 2 ft of space each soldier need in a pack formation, that is 5280 ft/2 ft per man = 2640 men, spread out for 50k men would be 19 ranks. A typical legion has 6 ranks of hastatii, 6 ranks of principes, and 3 ranks of triaii.

I don't think it is inconceivable at all.
I think you're misunderstanding me, I'm talking about the skirmishers. How does one deploy 20,000 skirmishers in front of a battleline smaller than the one at Trebia, where 8,000 were deployed on the wings and in front of the centre? Skirmishers can only be drawn up so deep. A max of say 10,000 skirmishers could feasibly occupy the front of the Roman heavy infantry, being generous. So the other 10,000 were likely either left in the camp or served as non-combatants, bringing food, taking away injured men etc.

Nonsense. There are any number of literary and practical reasons to doubt 16 legions and Alae at Cannae. It is simply Polybius vs Livy, Wallbank and Toynbee vs Brunt, DeSanctis and Hallward. I don't see anything convincing or new in Lazenby or Goldsworthy et al. It's simply a matter of what you want to accept.
Then let me convince you. This line of thinking would mean the Roman army at Cannae would amount to something like 44,000 according to Cantalupi, who AFAIK is the one who originally called for taking Livy over Poly. This would change the battle picture considerably. However, Livy's take isn't convincing. Hannibal was already feared in Italy, and it's very doubtful that Fabius' strategy was underhanded in order to march out against Hannibal with a numerically inferior force.

26,000 men arriving in Italy with Hannibal is the most accurate number you'll ever see in any primary source ever. Attested not only by Polybius, but by the monument erected by Hannibal himself on the Lacinian Promontory.
Nobody is doubting the authenticity of Polybius or the tablet, as I stressed in my post. What I'm saying is that the figure curiously missing the light infantry in Hannibal's army mentioned many times after the fact: on the Trebia, at Cannae etc. But if we try to fit those into the figure, we only get 12,000 heavy infantry for Hannibal, which doesn't add up to his later battles either. So it appears that the light infantry was left out of the calculation, for whatever reason. Though note that Caesar, Sulla and others would leave out light infantry in the counting of their army sizes for their memoirs.
 

tomar

Ad Honoris
Jan 2011
14,301
Livy xxii.36

The armies also were augmented. But how large were the additions of infantry and cavalry I should hardly venture to declare with any certainty —so greatly do historians differ in regard to the numbers and kinds of troops. Some say that ten thousand new soldiers were enlisted as replacements; others that four new legions were enrolled, so that they took the field with eight. Some assert that the legions were also increased in the numbers of their infantry and cavalry, and that each received an additional thousand foot and a hundred horse, bringing up the total of every one to five thousand foot and three hundred horse; and that double the number of horse and an equal number of foot were furnished by the allies. One thing is not disputed —that they proceeded with more energy and enthusiasm than in former years, because the dictator had given them ground for hoping that they would be able to defeat the enemy.


So in the case of Livy, the difference was between 4 legions or 10,000 men. That was the main contention between 4,200 * 4 vs 10,000, the difference is 6800.

Then if we were to consider that the allies were to match these numbers the difference would be a total of 13600 on that count.

However, it then mentioned that each legion received an additional thousand foot and a hundred horses, on the assumption that the Romans carried out their struggle with 6 legions (rather than 8) that would means there were 12,,000 foot, changing that difference of 13600 to the difference of 1600.

That is to say Livy's difference would be
6 Roman legions * (4200/legion + 1100) + 6 Allies ( 4200/legion + 1400) = 65400

Polybius asserted
8 legions of Romans at 5000 + 8 legions of allies at 5000 = 80000

Without considering over strengthen legions we would have
8 legions of Romans at 4200 and 8 legions of allies at 4200 = 67200

The dispute then isn't whether or not there are possible 8 legions taking the field, it's whether or not 8 strengthened legions took the field.



Brunt's argument was essential, it's impossible to win a battle 2:1 therefore we should take the Livy's view of strengthened legions rather than Polybius' 8 legions or 8 strengthened legions.

Brunt
"Livy had read that Roman army comprised either 4 legions strengthened by 10,000 recruits (of whom at least half would have been allies) or 8 legions, each 5500 strong, with proportionately large allied contingents, making an army of 8700. Polybius adopts the second view, and gives a total strength of 80000 foot plus (it appears) 6000 horses. The first account is to be preferred, not only for the reasons De Sanctis gives but because the success of Hannibal's tactics is unintelligible if the Roman forces outnumbered his own by two to one. Livy's details on casualties presuppose the large total; the rival estimate which must have been given by the authority for the smaller sie of the army is lost.'

Now I find this position questionable. For one, it presumes that a victory of that magnitude was impossible. Why?

Second, Hannibal's forces did not fight the entire Roman army, as 2 legions were detached by Rome which was attacking Hannibal's camp, and Hannibal left behind a smaller force (we don't know the actual number) that was resisting the Romans. Hannibal's infantry that fought against the Roman infantry was not a 2:1 ratio.

I don't have access to De Sactis or Cantaplupi, so you would have to quote these people, however, for Cambridge Ancient History vol 8, it wasn't written by Hallward, but rather John Briscoe

The six-month term of the dictator elapsed before the end of the consular year, and the armies of Fabius and Minucius reverted to the consuls M. Servilius Geminus and C. Atilius Regulus (who had been elected to replace the dead Flaminius). For 216 the new consuls were L. Aemilius Paullus and C. Terentius Varro. Polybius reports that it was decided to give the consuls a force of eight legions of 5,000 men each, which, with the same number of allied troops, meant a total force of 80,000. There is no need to doubt these figures and it is the size of the Roman army that made the third Roman defeat particularly devastating. Hannibal occupied Cannae, by the River Aufidus, an important supply base for the Romans in Apulia.


So ultimately Brunt rests his argument on 1) it's impossible to win a really hard fight and 2) what De Sanctis said.

So please give us what De Sanctis said.



This is pure speculation.



Do you have a source on how Polybius arrived at his number through backward calculations?



Isn't that a no True Scotsmen argument?




This army marched by the sea and was near a river. It could be perfectly be supplied from the coast.



The Roman senate took over the direction of the war after Cannae. Do you have a source that the consuls prior to Cannae was NOT in control of their war?




How many actual military commanders says this?
The problem with these calculations is that they assume that all units were at full strength or even overstrength....

This is not the case when wars are being fought..... As recently as WW2 , it was relatively common for units on the german or soviet side to be in the field with 20% or less of their theoretical strength... Without going to that extreme a unit would be quite functional with 60% of its theoretical strength...

For example when Caesar was fighing Pompey

By December 49, Caesar’s main problem was a lack of transportation. Remarking that “the most potent thing in war is the unexpected,” Caesar embarked seven understrength legions (about 15,000 men) with some 500 cavalry and supplies and sailed for Greece on January 4, 48 BC ,,

In this example Caesar's legions are at 50% of their theoretical strength


This author theorizes that in 212 BC the roman legion were understrenghth and numbered "perhaps 3200 men"

Many more such examples can be found

The point is: roman legions were rarely at full strength and if they were , it did not last very long.....
 

mariusj

Ad Honorem
Aug 2015
2,057
Los Angeles
The problem with these calculations is that they assume that all units were at full strength or even overstrength....

This is not the case when wars are being fought..... As recently as WW2 , it was relatively common for units on the german or soviet side to be in the field with 20% or less of their theoretical strength... Without going to that extreme a unit would be quite functional with 60% of its theoretical strength...

For example when Caesar was fighing Pompey

By December 49, Caesar’s main problem was a lack of transportation. Remarking that “the most potent thing in war is the unexpected,” Caesar embarked seven understrength legions (about 15,000 men) with some 500 cavalry and supplies and sailed for Greece on January 4, 48 BC ,,

In this example Caesar's legions are at 50% of their theoretical strength


This author theorizes that in 212 BC the roman legion were understrenghth and numbered "perhaps 3200 men"

Many more such examples can be found

The point is: roman legions were rarely at full strength and if they were , it did not last very long.....
If you tell me that in the middle of a year Roman legions were not at full strength, sure, but if you are going to tell me that prior to Cannae, when the consul promised to take the fight to Hannibal, and we know there was a huge drive to raise troops and fill the legions if you are going to use that excuse that Roman legions were understrength, I don't buy it.
 

Duke Valentino

Ad Honorem
Jul 2017
2,367
Australia
Yes, there’s no reason to believe that the Romans increased the number of heavy infantry in the legion to only levy under strength legions for Cannae.
 

tomar

Ad Honoris
Jan 2011
14,301
Yes, there’s no reason to believe that the Romans increased the number of heavy infantry in the legion to only levy under strength legions for Cannae.
Well one pointer is that the romans are reported to have left 2 legions to guard their "camp" (or alternatively to raid Hannibal's camp if the opportunity arose depending on versions)... while it was standard practice to do so, 10 000+ men is way over the top for such a mission.... If however these were understrength legions ,then it makes more sense
 

mariusj

Ad Honorem
Aug 2015
2,057
Los Angeles
Well one pointer is that the romans are reported to have left 2 legions to guard their "camp" (or alternatively to raid Hannibal's camp if the opportunity arose depending on versions)... while it was standard practice to do so, 10 000+ men is way over the top for such a mission.... If however these were understrength legions ,then it makes more sense

Make sense if there isn't room to put them in the formation and why not open a second front and force Hannibal to weaken his troops? There are roughly 19,000 captured soldiers, make perfect sense if a decent portion came from these 10,000 men.
 

tomar

Ad Honoris
Jan 2011
14,301
Make sense if there isn't room to put them in the formation and why not open a second front and force Hannibal to weaken his troops? There are roughly 19,000 captured soldiers, make perfect sense if a decent portion came from these 10,000 men.
Not sure what is the source for the 19 000 number, but indeed Polybius claims that almost all of them were captured (so much for that second front)... Also he claims they could not succeed in attacking Hannibal's camp because he had left it under guard ..... Which seems strange, Hannibal did not really have men to spare considering how outnumbered he was supposed to be, so how many men could there have been in the camp to hold off an attack by 2 whole legions ?


The ten thousand Romans who were captured had not,

as I said, been engaged in the actual battle; and the reason was this. Lucius Aemilius left ten thousand infantry in his camp that, in case Hannibal should disregard the safety of his own camp, and take his whole army on to the field, they might seize the opportunity, while the battle was going on, of forcing their way in and capturing the enemy's baggage; or if, on the other hand, Hannibal should, in view of this contingency, leave a guard in his camp, the number of the enemy in the field might thereby be diminished. These men were captured in the following circumstances. Hannibal, as a matter of fact, did leave a sufficient guard in his camp; and as soon as the battle began, the Romans, according to their instructions, assaulted and tried to take those thus left by Hannibal. At first they held their own: but just as they were beginning to waver, Hannibal, who was by this time gaining a victory all along the line, came to their relief, and routing the Romans, shut them up in their own camp; killed two thousand of them; and took all the rest prisoners. In like manner the Numidian horse brought in all those who had taken refuge in the various strongholds about the district, amounting to two thousand of the routed cavalry.
 

mariusj

Ad Honorem
Aug 2015
2,057
Los Angeles
Not sure what is the source for the 19 000 number, but indeed Polybius claims that almost all of them were captured (so much for that second front)... Also he claims they could not succeed in attacking Hannibal's camp because he had left it under guard ..... Which seems strange, Hannibal did not really have men to spare considering how outnumbered he was supposed to be, so how many men could there have been in the camp to hold off an attack by 2 whole legions ?
19000 came from Gabriel, it is perhaps the entirety of the captured prisoners as I have noted previously that the 2 legions were perhaps a portion of that number.

Second, it's much easier to defend a position than it is to attack one. After all, we are talking about within a day. So you probably need a lot less man and noted, it was getting shakey until Hannibal roll in.