"Caesar's 4-3-3 cohort formation" Topic

I've notice, especially amongst "To the Strongest" players, bases with 2mm blocks arrayed in Caesar's 4-3-3 cohort arrangement, that is four cohorts in the first line, three cohorts in the second line and three cohorts in the third line.

Unfortunately, this array has never really been scrutinized by academics and wargamers alike. Academia's adaption of Caesar's 4-3-3 arrangement has then led to two schools of thought, one, that the Romans fought with gaps in the line, and the other, there were no gaps in the line. If the Romans fought with gaps in the line as standard, then there would be no point in making gaps in the line for the infantry or cavalry to pass through.

Caesar's 4-3-3 formation was employed at Ilerda. Caesar' (BC 1 83) reluctant to fight writes:

"even if the enemy were driven to flight, a victory could not greatly promote his final success. For the two camps were distant from one another not more than 2,000 paces. The two lines occupied two-thirds of this space; the remaining third was empty, left free for the onset and charge of their troops. If battle were joined, the propinquity of the camps afforded the conquered a speedy retreat in their flight. For this reason, he had made up his mind to resist them if they advanced their colours, but not to be the first to attack. The Pompeian line was a double one of five legions. The third line of reserves was occupied by the auxiliary cohorts. Caesar's line was threefold, but the first line was held by four cohorts from each of the five legions. Next to these came three reserve cohorts, and again three more, each from its respective legion; the bowmen and slingers were enclosed in the centre of the force, while the cavalry protected the flanks.")

When facing the Pompeian army of five legions at Ilerda, Julius Caesar comments that the Pompeian line was a double one of five legions. As the Pompeian army only had five legions present at Ilerda, this means of the 10 cohorts in a legion, the Pompeian legions were arrayed five cohorts wide by two cohorts deep.

Caesar also had five legions, so, in order to match the Pompeian frontage, Caesar would also have to array his five legions, five cohorts wide by two cohorts deep. However, what concerned Caesar was that as he states the Pompeian "third line of reserves was occupied by auxiliary cohorts." This means Caesar did not have a third line, and earlier, Caesar claims that the Pompeian auxiliaries amounted to ‘about' 80 cohorts. So, from this, we can take heed that Caesar's 4-3-3 was not the legion's standard array, but a formation adapted to the tactical situation Caesar found himself in at Ilerda.

This leaves us with what would be Caesar's best option. For me, I would copy what he did at Pharsalus, arrayed Caesar's five legion in the five by two cohort arrangement. That way I have matched the Pompeian frontage. Then I would take the back ranks of men from each cohort, and with them form a third line. This would mean Caesar's three lines would be thin, but it does give Caesar a reserve line if he needs it. Fortunately for Caesar, no battle occurred.

I suspect you are referring to 'Strength and Honour' rather than 'To the Strongest'. In terms of how the cohorts are arrayed on a base, I'm afraid I had a bunch of cohorts, a set base-size, and I made them fit, in a few different configurations so that I could differentiate different quality troops.

There is a reference in Caesar's Gallic War to a battle line arranged in "quincunx" i.e., like the spots on a 5 dice. So it was a common Roman formation, or at least, more than a one-off. There is more than one interpretation of quincunx, though, and I would check the Latin to make sure all that detail is there, not just a translator's elaboration of quincunx

I covered this in my book Ancient Battle Formations. Let me just reproduce the relevant passages here:

"Against the above model it is generally assumed that there were four cohorts in the first line, three in the second and three in the third, following Caesar's description of his deployment against Afranius in Spain. A careful reading of the passage however indicates that this deployment was unusual.

"Acies erat Afraniana duplex legionum v, tertium in subsidiis locum alariae cohortes obtinebant; Caesaris triplex; sed primam aciem quaternae cohortes ex v legionibus tenebant, has subsidiariae ternae et rursus aliae totidem suae cuiusque legionis subsequebantur.

"Afranius' five legions were in two lines. The third line was in reserve with the cohorts occupying the place of the wings. Caesar had three lines, but the first line had four cohorts from each of the five legions, behind it the reserve had three and the following line the same number, each from their own legion. – Commentaries on the Civil War: 1.18.

"Notice the ‘but'. This means that Caesar deployed in the standard three line arrangement, however the distribution of his cohorts in each of the three lines was not standard, and he goes into some detail describing it. It is possible that Caesar's novel deployment was a clever means of countering Afranius' concentration of his third line on his flanks. This was meant as a guard against Caesar's superior cavalry, but could also have been used to envelope Caesar's infantry a la Cannae whilst Afranius' cavalry kept Caesar's horse busy. If Caesar's second and third line deployed about 5 men deep, that would free up five cohorts per line to counter Afranius' reserve, but without Afranius being aware of the fact."

The Marian (or Caesarian) legion was a development of the Polybian legion:

"The contubernia are the right size for file units, hence the first two lines probably deployed with the contubernia as files, creating a line about 10 ranks deep. Each cohort thus deployed about 48 yards wide and the entire legion occupies a frontage of 192 yards. The third line, deploying 5 ranks deep in half-contubernia would not have found its lack of depth a problem since after the retirement of the first two lines it would have been reinforced by an additional 20 ranks. Frontinus affirms that Pompey deployed his three lines each ten men deep at Pharsalus (see Diagram 130). This is possible if Pompey deployed three cohorts in each line and split the tenth cohort between the three lines, the greater depth presumably to narrow the frontage of his more numerous legions to match that of Caesar.

Diagram 129: The Marian legion.

Diagram 130: Pompey's deployment.

"This incidentally is the only reference in the sources to the depth of a triplex acies Roman line in regular battle order. Arrian's mention of a legionary battle line 8 ranks deep in his Array Against the Alans describes an experimental formation used in 135 ad that was to become the single line anti-cavalry arrangement of the late-Roman army, in which heavy infantry in the front ranks, armed with a large pilum and later a spear, employed the foulkon to repel cavalry whilst missile armed infantry in the rear ranks with archers at the back shot overhead."

Advocate: I suspect you are referring to 'Strength and Honour' rather than 'To the Strongest'.

Oh, my apology to "the Strongest." Seen and read too many rules in the last 3 months, that they are now blurring into one.

Dagwood: There is a reference in Caesar's Gallic War to a battle line arranged in "quincunx" i.e., like the spots on a 5 dice. So it was a common Roman formation, or at least, more than a one-off.

Going from memory, I believe Caesar uses it in his description of one element of his siege works at Alesia. There could be another source using it to describe a row of trees. Other than that, no ancient source actually states the use of a chequer board or quincunx in relation to military matters. Livy description of the legion and the passage of lines does not employ the term. One can find references to centuries, maniples, cohorts, ordines and vexilla, so if it was standard, you would expect to find more examples in the ancient sources.

The ancient sources do tell us what the correct name is for the formation, but alas, it is ignored by all and sundry, except for me.

Bolingar: I covered this in my book Ancient Battle Formations. Let me just reproduce the relevant passages here

Now when it comes to the 4-3-3 formation and how many men in a legion during Caesar's lifetime, and how it was organised, you and I are a couple of light years apart in our thinking.

@The Trojan

Now when it comes to the 4-3-3 formation and how many men in a legion during Caesar's lifetime, and how it was organised, you and I are a couple of light years apart in our thinking.

No doubt, but I'm happy to substantiate my thinking by reference to the primary sources, in the original language.

The quincunx for example is a complete fabrication by historians. The term was never used and the formation never described by authors in Antiquity. I'm happy to go down this rabbit hole if anyone wants. Alternatively, feel free take a shortcut and check out the chapter on line relief in my book. ;-)

The ancients could have done a better job of keeping us informed, couldn't they?

@rustymusket:

They took a lot for granted assuming their audience already knew it. You can be sure that whenever the authors describe a Roman deployment in detail, they are describing something unusual and not in the line of a standard formation – which their readership was already quite familiar with.

Interesting discussion. I have wondered why the rules I have read happily charge you more points for a Roman soldier and make him more effective than other nationalities, but do not seem to require the checkerboard formation, which helped to make him a superior soldier.

Grelber

Trojan, quite right, it was the booobytraps that were in quincunx, not the soldiers.

Bolingar: No doubt, but I'm happy to substantiate my thinking by reference to the primary sources, in the original language.

Yes, that is also my discipline, follow the primary sources. Your advantage is knowing Latin, I'm too busy learning Japanese.

Bolingar: The quincunx for example is a complete fabrication by historians. The term was never used and the formation never described by authors in Antiquity. I'm happy to go down this rabbit hole if anyone wants. Alternatively, feel free take a shortcut and check out the chapter on line relief in my book. ;-)

I am always left astounded by the machinations of academia. They literally impose their own interpretation and terminology onto the primary sources, and yet ignore what the primary sources are trying to tell us. So, what do the primary sources say about Roman formations? Aulus Gellius (10 9), names a few Roman formations, of which one is called Serra, meaning saw.

Vegetius (3 17), mentions the Serra formation, and at (3 19) Vegetius (3 19), describes the Serra "as the name of a formation which is ranged by crack troops before the front, facing the enemy, so that a disordered line may be repaired."

On the Serra formation, Festus (466 28L) writes: "To fight in saw-formation is said when there is a constant advancing and withdrawing, and no standing still at any time."

Rusty musket: The ancients could have done a better job of keeping us informed, couldn't they?

Mate, we are waiting on you do get the time machine built. I would do it, but other things just keep popping up that require my utmost attention.

Grelber: Interesting discussion. I have wondered why the rules I have read happily charge you more points for a Roman soldier and make him more effective than other nationalities, but do not seem to require the checkerboard formation, which helped to make him a superior soldier.

The Romans were not the only ones that replaced fatigued troops with fresh ones. From memory, there is an example of Hannibal's army doing this. I think it was in Livy. I believe all armies must have had a system of replacement. The Macedonian phalanx could not just fight a whole battle leaving the first five ranks to do all the fighting. All Macedonian phalanx sizes (8, 16, 32 ranks etc) are divisible by four, so could have a rotation system based on each four ranks.

Found in Livy's books 30 to 40, is extensive, and I mean extensive and consistent data concerning the Roman replacement system for legions serving abroad. In fact, data also exist of this happening in Italy during the Second Punic War. I have studied this data for some years, and have been able to fathom how it works. Generally, veteran troops are referred to those troops who have completed or are undertaking the last required number of campaigns.

In 449 BC, Livy (3 57) states that the levy was so popular that: "not only did the men liable for service promptly give in their names, but a large part of the levy consisted of men who had served their time and came forward as volunteers. In this way the army was strengthened not only in numbers but in the quality of the soldiers, as veterans took their places in the ranks."

In 406 BC, according to Livy (4 58) in defiance of senate's pressure for a declaration of war against Veii, the tribunes of the people asked the veterans how many campaigns they had undertaken and what blood was still left for them to shed for the State.

In 180 BC, Livy (40 40) writes that the time-expired men were released from their military oath.

In a nutshell, the data from the primary sources reveal that the Romans have in each legion an equal number of troops undertaking a particular campaign period. The next question that arises, is how are these various troops undertaking a particular campaign period positioned within the legion. It worked out that the troops undertaking their last campaign period, that is the troops that had served the most campaigns, were placed in the front ranks, leaving those raw or green troops stationed in the last rank of each century.

In the old days, that is before the introduction of the hastati, each battle line in a legion consisted of men undertaking the same campaign divisions. This meant, the last battle line consisted of all the raw troops, or those with the lest number of campaigns being undertaken.

When fighting the Volscians in 483 BC, Dionysius (8 85) reports that "the centuries that were last and guarded the rear, stopped to strip the dead." The last line of centuries are those centuries with the least number of campaigns served, and therefore, less disciplined.

Trojan, one problem is that the "Roman" army existed over more than a thousand years. It evolved greatly over that time. Comments in Vegetius are not likely to be applicable to the fight against the Volscians.

Dagwood: one problem is that the "Roman" army existed over more than a thousand years. It evolved greatly over that time. Comments in Vegetius are not likely to be applicable to the fight against the Volscians.

Can you prove that Vegetius isn't applicable during the time the Romans fought the Volscians? You say the Roman army evolved over 1,000 years. Can you define how the Roman army evolved, and when these evolutions occurred?

Vegetius covers the legion's structure from the Polybian era (3 lines) to the mid-imperial era (2 lines) and the late-imperial era (1 line with reserves behind the centre and wings. He doesn't cover the earlier Republican era – 2 lines then later 5 lines (Livy) – or the monarchy (a single hoplitesque line without line relief).

Vegetius confuses the Polybian and mid-imperial legion structures, affirming the legion has two lines but that triarii are deployed behind these lines without constituting a third line. He is clearly trying to reconcile different sources that describe different periods of the legion's history. It's not difficult however to disengage the components from each era and form a picture of the legion's development.