Cannae - why bother with the cavalry?

[Macedon]

Appian is discussing the Roman infantry being deployment in three lines before the battle commenced. Why does he have to continue to speak of the light armed infantry after they are withdrawn? Does Polybius tell us anymore of the velites after they dealt with the elephants? No he doesn’t. The fact the light armed started the battle is attested by both Livy and Polybius. You cannot reconstruct Cannae by only employing Appian. How many lines does Livy or Polybius speak of? Who breaks through the Celts after the apex of the wedge is defeated? Unfortunately Appian, Livy or Polybius do not tell us.

No problem with that. Just making clear that you also do not base your model on the three lines of heavy infantry described by Appian. I do the same thing. In my opinion, even if in the beginning they did deploy in their "traditional" triple acies, they later chose to form one line. In yours two.

I have other translations done for me and they have the maniple many times deeper than its frontage and the maniples closer together.

"πυκνοτέρας ἢ πρόσθεν τὰς σημείας καθιστάνων, καὶ ποιῶν πολλαπλάσιον τὸ βάθος ἐν ταῖς σπείραις τοῦ μετώπου·" The Greek text is very clear on this "He arranged the semaeae (maniples) more dense than before and the depth of the speirae (maniples again) (many) times greater than their frontage" So, we are talking about the soldiers in the maniples being arrayed closer to each other (which could be close or compact order) and practically in column. I still cannot see it as arranging the lines closer to each other, without of course claiming that they were not, I have them unite the lines myself. I only speak of the translation of the said text.

I have provided the Frontinus reference of Hannibal creating gaps at Trasimene for the Roman army in part to escape to show he would have learnt from this and not to repeat it at Cannae. Even the Mongols knew that you must allow space for a surrounded army to try and escape through (giving hope) otherwise they will furiously fight to the death when they know there is no possibility of escape. I do not believe Hannibal wanted to completely trap the whole 14 legions in one pocket. As I see it, as the Romans were fleeing and being killed, the pocket got smaller and the Africans overtime kept extending until the gap was closed.

Of course, I have scores of such examples and pieces of advice, However, in the texts, the terms "flank-attack" and "encirclement" are more vague than commonly perceived. It is especially clear in the later manuals that when troops attack the flanks of an enemy formation, they also often attack the rear too. So it is not about a long line engaging the few men forming the outermost file of the enemy. Wanting to completely trap the legions does not mean that you do that with infantry only. In this I personally choose the cavalry scenario, that is, that Hannibal completely surrounded the Romans with his cavalry (where his infantry was not engaged), who of course did not remain stationary as in some kind of phalanx but kept maneuvering back and forth as they used to do, giving the impression of hope as the space between them and the trapped Romans was empty, as was the space between the squadrons. The fleeing Romans, thousands and thousands of them, tried to escape through them, were mercilessly attacked and hacked down, resulting in the huge number of casualties we know of. Of course, some of them, those who were able and had the clear mind or experience to keep together in a body were able to retreat through the enemy cavalry formation as also did some riders of those who had not fled in the beginning. So, "a complete encirclement" does not of course tactically mean that they were "completely surrounded" by an uninterrupted chain of men.

Gary Brueggeman’s insightful website has a very interesting discussion on cavalry attacking the flanks of the infantry. It shows how only a few cavalry can actually attack a flank, with the majority of the cavalry having nothing to attack but thin air. At Cannae, a lot of the African infantry would be in the same position with nothing to attack. A flank attack is synonymous with attacking the flank and rear of a unit. Livy’s comment about the Africans extending does indicate they are being to encircle the Romans. In my book, I do not just state the Africans extend and leave it at that, I go into detail via diagrams as to how in the most simple and fast manner they could accomplish this. Here you will find I am strongly influenced by the Gary Brueggeman approach (don’t just state it, show it). This is where those military manuals come into play. Also in my study of Zama, I don’t state the Romans formed a single line, I detail it in diagrams how it could be done. This exercise produced a little surprise. Same with Ilipa, I give the numbers of the troops involved in the outflanking movement, their formations and how they wheeled, and most importantly, what the outflanking forces were trying to achieve.

I agree with this. I also have such an approach on tactical matters, very mathematical, diagrams, thousands of specially prepared 6mm miniature blocks to play with numbers and ratios, distances and angles. The question regarding Cannae is the shape of the Roman formation once they broke into the enemy. If their line became a crescent or if units broke off, then a flank attack in line is very understandable as there would have been Romans extending over a lot of space in a vertical axis to their original formation. And then we would also have the pushing advancement of the Libyans on the flanks as they marched towards each other. That some of them would be able to, and why not, form at an angle to enclose the enemy I find very possible. The question would be how many and how long they would extend. As much as I see it a natural consequence of events and of Hannibal's plan, I also see it as a secondary maneuver, taking into account that the cavalry had already adequately covered the "ground for escape", giving the Romans a false ray of hope, which is consistent with the tactics we mentioned above.

There has been a tradition among historians of the cavalry completing the encirclement. What are the cavalry doing? Are they standing stationary horse shoulder to shoulder so to form an unbreakable line while dispatching the Roman infantry? This scenario lacks common sense and only possible in the mind of the beholder, like Sir Walter Raleigh. I have come to the conclusion that when the Carthaginian cavalry returned to the battle, they were running down those Romans fleeing the pocket, and were not creating a wall so as to prevent the Romans from fleeing. I also don’t have the Africans completely encircling the Roman infantry. My study shows the Africans don’t have the numbers, therefore the frontage to do this properly. It is only after the pocket has been severely reduced can the Africans accomplish this.

They form a wall in squadrons, which is an "invisible" wall. The Romans think that the way is open, that they can flee, but as they try to run through the open space where they see no enemy cavalry, they are attacked by them. I have given more details on my opinion on this above.

The Roman infantry have the same frontage as the Carthaginian infantry.

Where did you get the figure of 32,000 Celts? Why do you believe the 32,000 Celts are deployed in a single line? What happened to the wedge formation? Taking your army numbers, if the field of Cannae can only allow a frontage of 1000 men, then your 32,000 Celts would be deployed 1000 men wide by 32 ranks deep. Your 50,000 Romans would be deployed 1000 men wide by 50 men deep.

At the Trebia, Hannibal had over 20,000 men, at Cannae over 40,000 men. At the Trebia the Romans had eight legions, at Cannae 16 legions. So both armies had doubled their infantry. At the Trebia the Roman broke through the Carthaginian line. This leaves the question as to why did they believe they had to deepen the depth of the maniples at Cannae.

The over 40,000 men at Cannae included the about 8,000 Libyans waiting behind the crescent. The rest are about 32,000 men. The wedge formation is in itself a battle-line, especially if it was a crescent shaped line as also described instead of detached smaller lines at a distance to each other. The question remains, these 32,000 men extended over a certain length of ground from the apex to the ends of the wings in two axes. Their frontage of course is only the axis parallel to that of the Roman frontage. So, in your model, is the total frontage of the whole Carthaginian infantry formation equal to that of the Romans? The field was quite extended, especially since the battle did not take place at an angle perpendicular to the general river flow (that is east-west) but more like parallel to it (north-south). So the lines themselves extended much longer than the distance between the river and the hills of Cannae. Anyways, we of course are unable to know the dimensions of the real battle-ground but at least according to all descriptions, it must have been quite extensive, whatever that could mean here. It certainly nowhere is described as narrow for such numerous armies.

Yes the first line (the hastati) will have less men than the second line (principes/triarii). However, this does not affect the legion’s frontage. Following Polybius, if you have 1200 hastati in a legion and 1200 principes, and you decide to deploy them 200 men wide, the hastati and principes both have a depth of 6 men. This means the 600 triarii have a depth of three men, and when the principes are combined with the triarii, the principes and triarii have a combined depth of 9 men. The legion then has a frontage of 200 men and a combined depth of 15 men. If you include the 1200 velites, then they would be deployed 200 men wide by 6 men deep. Now the legion has a combined depth of 21 men. In board game jargon, all legions have a zone of control. With a legion having a frontage of 200 men, 14 legions have a frontage of 2800 men. Now you need to implement Polybius’ maniple arrangement for each legion and in doing so each legion and therefore each line within a legion will have the same frontage. So the hastati will end up having the same frontage as the principes and triarii, accept the principes/triarii have a greater depth. The formula I found is when the Romans increase the size of the legion; they increase the depth, not the frontage. In this manner, they do not have to increase the number of centurions or centuries.

Yes, this more or less coincides with my calculations and understanding. I also believe that the extra men are used for added depth. However, the question as to the frontage of the Roman infantry line at Cannae remains, where the line was arrayed much deeper than usual, making the frontage maybe 1/3 to 1/4 what was "normal". This does not mean that there was no regulation ordaining such an event, of course there would have been, but if a line of Hastati (2/7 of a legion) was what made up the front of the Roman line alone, then we are talking about more or less 23,000 men, the rest standing in reserve behind them, a good distance away. If these 23,000 men arrayed in extra deep, dense files as the texts say, then we are talking about a frontage normally held by correspondingly less men. Against them Hannibal arrayed about 32,000 allies, so, in order for the two lines to have the same length of frontage, the Carthaginians should be arrayed even deeper/denser! This is a mathematical problem I cannot solve unless I assume that at least a good number of the men on the rear, if not all, joined the Hastati in the first line. Else, I have a Roman line for some reason much shorter than that of the enemy, which was a tactical possibility, but would have been commented on as a stratagem. How have you worked this issue out, so that the two lines are similar in length?




I will not comment on your theory regarding deployment mathematics, we have been through this before and of course it would be unfair to say anything before I can read it as a whole, although I still do not understand the 6 squadron depth. Do you mean 6 squadrons one behind another as in 6 successive lines? Do you mean that they joined in a single squadron that was 6 times larger and deeper than a single one?

I turned the quotes into italics to make them easier to read, so no worries.