Overview
A short guide to the Late Republican Roman Legion, from the marian reform to the augustean system.
Preface
In this short guide i’ll try to explain how to field a roman army, as close as possible to the ones that were deployed during the final century of the roman republic. In each part i will explain the historical basics (and tactics) of the three examples (marian’s cesar’s and augustean’s legion), and the way i’ve found to recreate them in Rome 2.
I apologize in advance for every mistake (mostly grammatical, since i’m italian and not english!), and i thanks anyone who will give a look at this guide.
The Marian Reform – Historical Background
Since the founding of Rome the roman army was deployed following the social (and, thus, economical) status of its citizen, spanning from the wealthy equites to the poorest levies amd skirmishers. With the uninterrupted expansion of the Republic, this sistem was too strongly tied to the business of its own citizens, and long military campaigns were difficult to accomplish.
When the Republic found itself at war with Giugurta, king of the numidians, few citizens were interested in fighting a war in a desert region, with few possibilities to be rewarded with lands and spoils. The II century BC itself saw the constant reduction of the minimum whealth requirements to enlist, since more men where required to fight against the Chartaginians first, then against the Macedonians and the eastern powers.
Mario. the designated leader of the army against Giugurta, took the decision to recruit the new troops capite censi ( “counted by the head”, meaning that they were counted only for themselves and not for theyr wealth) charging the Republic of the weapons and provisions.
He also eliminated the previous three-unit system (however the Hastati and the Principes were already melted in practice) raising a legion made only of heavy infantry, and started a long series of training never saw previously in the republican army (thus the Marian legionnaires were called “Marian Mules”).
He adbandoned the Manipular system, in favour of a Cohortes-based one (a cohors, litterally, is an animal enclosure), where each cohort was made of 3 maniples, a 480 men-strong force at his maximum.
The new Legions were allowed to take a name and to bring in battle their own banner (jointly with the eagle banner that Mario gave them), laying the foundations to the well known professional Legions of the Empire.
Since the new Legionnaires were professional soldiers, and no more citizen provided to the army, during the I century BC the roman army acquired an undisputed superiority against all other Mediterranean powers (and beyond), while during the middle and early republic, many foes were able to match and defeat the roman army (like the Chartaginians): the only real enemy left to the it, were the Legions themselves, now more loyal to their commanders, whom provided most of their equipment and wages while the senate was slow to acknowledge the new standing army, paving the way to the civil wars that marked the dawn of the republic.
The Late republican-Augustean Legion – Army composition
A single legion was made of 10 Cohortes, (nominally 4800 men), where each cohort was the melting of three maniples (thus 6 centuriaes of 80 men). The Cohort itself was probably already used at least since the Second Punic war, when probably was just a way to detach a temporary force stronger than the maniple but not as big as a whole legion (practice that will see a wide use in the Empire). Cohortes were in fact stronger than a single maniple, and easier to command for a general (since he was giving orders only to 10 Cohortes’ Commanders and not to 30 Maniples’), On the battlefield they acted like a single unit (not like three separated maniples) being more effective this way.
The First Cohort was usually bigger than the others (mostly on later armies, in fact), because it was usually made of expert legionaries, used to build war machines, brideges, cooking and everithing that was needed in an army . Also those legionaries did not have to work like the orthers, being they precious for the Legion survival.
The First Cohort, bearing the legion Eagle (Unit size inreased to 500 men)
The smaller unit was the Contubernium, made of eight men (thus 10 contubernium made one centuria). All of the men in a contubernium lived together, sharing the same tent (contubernales) in the camp and servants, eating tocether etc. (similar to a modern day squad), and were commanded by a decanus. The commanding officer of a centuria was the Centurion, helped by the optio (sort of second in command), singifer (or standard bearer) and the tesserarius (watch commander and third in command); those were called principales, and were the senior officers of each centuria. The commander of a cohort was probably the highest ranked centurion (or pilus prior) or maybe the eldest one. Promotions were made through the cohorts, so that a soldier promoted to a centurion rank from the I Cohort, received the command of a centuria from the X cohort, or even moved away to a less experienced legion. Those in the I Cohort were the primis ordines (the commanding centurion the primus pilus) and were one of the highest ranking officers in the whole legion (and thus the centurion was a coveted role).
Above those officers were five tribunes called augusticlavi (of equestrian social class), and one prefect. Those roles were given for political or merit reasons as well (while the centurions were career officers): the tribunes were usally made in command of vexillationes (units detached for a certain task) or helped the legion commander, the legate, commanding the Legion.
The Marian reform removed the roman legionary cavalry (also helped by the fact that, after the social war of 91 bc, every inhabitant of Italy received the roman citizenship) and the Legions started to rely on allied or mercenary troops. Augustus reintroduced a legionary cavalry, albeit smaller than the 300-men strong republican cavalry olf the manipular legion, being made only of 120 horsemen.
Auxiliary Spearmen behind a Turma of Auxiliary cavalry (with numidian Archers)
Before Augustus, Auxiliary units where organized depending on the needs of the moment, lacking a proper structure like the Legion itself.
The Augustean reform created auxiliary Cohortes, making them fixed units: those new units were now professional soldier, serving for many years, unlikely the early “social alae” system.
The single auxiliary units, being them cavalry or infantry, were usually detached to one legion, serving for long period of time (even more than the regular legionaries, since auxiliary troopers were required to serve for 25 years before being able to gain the citizenship and return to their families, instead of the 16-20 years of citizen-legionaries), and subsequently the auxiliary units were organized in a similar fashion like the cohortes: Cohortes Quigenaries (with 6 Centurias of 80 men) or Miliares (with 16 Centurias) for infanty based units and Alaes Quigenaries (16 Turmes) and Miliares (32 Turmaes) for cavalry units, not anymore the big sized units like the early Republican Alaes.
About Cavalry units each turma numbered around 30 men (thus from 500 to 700 horsemn). An in-game implementation is easier to achieve here, since (at the maximum scale) each cavalry unit number 80 men: fielding 5 or 6 units (around 400-500 men) seems fair, also keeping a tactical usefulness, but more can be used (eg if you are fighting against mounted enemies).
Auxiliary Cavalry could be used like common auxiliary cavalry, since all of the cavalry units in the legions were called Auxilia. However, in the late Republic, actual roman or italian (“social”) cavalry was uncommon (almost never used anymore), and the legions relied broadly on allied (and thus regional, as explained afterward) cavalry.
The legions were often (if not always) matched by support units from the conquered peoples and allies, especially as regards the cavalry: gauls, germans spanish and Numidic horsemen where the most used (often like explorers and to support cavalry strikes) but also cretan, batavian and syrian were used as well, depending on the local availability.
In fact there was no real difference between cavalry units: all of them were called auxiliary an one should feel free to choose them depending on the region where the legion is fighting: the Forest-dense german region gives different tactical challenges than a desert in the middle east.
During the empire auxiliary units were often moved between the legions (usually to keep them away from their homeland so to reduce chances to revolt) and wasn’t unusual to find numidic or spanish horsemen fighting against a german tribe or parthian raiders
An Auxiliary Ala (Quigenaria)
Infantry auxiliary units were used as well, especially regarding missile units (like cretan archers, or balearic slingers) and usually their numbers matched (or even outmatched) the Legionnairs’.
However, since the main body of a roman army was already made of heavy infantry, infantry auxiliary unit were often relegated to minor roles, like defending the encampment (indeed an important and not-so-minor task), patrols (cavalry above all), harassing the enemy before the main clash (skirmishers and missile units), guarding the flanks and in general everything that an heavy infantry force could not do.
It is important to notice that there wasn’t a broad difference, regarding the equipment, between auxiliary and legionnaires (given the obvious differences in weapons and armours between a light and an heavy infantryman) : except for those who brought their own weapons (like, probably, archers and slingers) legionnaires and auxiliaries shared the same smiths, shieldmakers, tanners and tailors.
Again, auxiliary spearmen can perfectly stand for common auxiliary infantry (with no strong ethinc warfare abilities).
Raising a Late Republican Army in Rome 2
Like explained in the previous section, a good way to start is to raise 9 Legionary Cohort and 2 First Cohort (or Eagle Cohort), with a mounted general.
It is my opinion that veteran (or evocatti) units should not be used, since i prefer to forge veteran troops battle after battle.
However, a legion made of Veterans (or with some veterans units instead of normal ones) may be raised in dire times, when the Republic (or the Empire) was in need of excellent troops as soon as possible.
This take up 12 slots (11 for the legionaries, 1 for the general) and leaves only 8 slots free for auxiliary units and, possibly, artillery.
Now you should take a decision: where is this legion going to fight? Against who?
At least an Ala Quigenaria of cavalry should be considered in every case (ie 3 cavalry units), while at least two (6 units) or an Ala Miliaria (5 units) should you be fighting against mounted foes.
Mounted skirmishers (or even archers) were common, so at least one unit of each Ala should be made of those horsemen.
Again, at least two sirmishers units (slingers or archers) are required, also to protect the Legion from war elephants. Their role was mainly to “mantain contact” with the enemy, allowing the Heavy infantry force to charge and defeat him.
We now have:
General (mounted)
9x legionaries (or veterans)
2x First Cohort/Eagle Cohort
3x Cavalry (1 should be missile)
2x skirmishers (slingers or archers)
The last three slots should be filled with another Cavalry Ala (3 units) should you be fighting against mounted or otherwise fast enemies, or with some Auxiliary infantry Cohort (1 units each, or 2 unit should it be Miliaria), possibly spearmen.
If you want to include artillery (that was quite common in the Late Republican professional army), one unit should do, if you are not building a siege army. In this case reduce the number of auxiliary infantry to only 2, and include one unit of ballista (definitely the most common type of artiller used in the roman and ancient world).
An Ala Miliaria of Cavalry can be used instead of two Alae Quigenarie, leaving 1 slot free for artillery (a ballista again) or of for anotherskirmisher unit, giving more flexibility to the army.
The final Legions should be like:
General (mounted) (Legatus’ guards-praetorians)
9x legionaries (or veterans) (Cohortes from II to X)
2x First Cohort/Eagle Cohort (I Cohort)
3x Cavalry (1 should be missile) (Ala Quigenaria)
2x skirmishers (slingers or archers) (Auxiliary Cohort-Quigenaria)
3x Cavalry (Ala Quigenaria)
OR
2X Auxiliary Infantry (or regional equal) (Auxiliary Cohort-Quigenaria)
and
1x Ballista
Otherwise
General (mounted) (Legatus’ guards-praetorians)
9x legionaries (or veterans) (Cohortes from II to X)
2x First Cohort/Eagle Cohort (I Cohort)
5x Cavalry (1 should be missile) (Ala Miliaria)
2x skirmishers (slingers or archers) (Auxiliary Cohort-Quigenaria)
1x Ballista
Note: the lorica segmentata was probably not used during the republican period (since archeological findings can be datde back only to the first century of the empire), and the legionaries and auxiliaries were armed with a chainmal called lorica hamata or, in the case of elite troops or officers (like centurions), a scales armor, the lorica squamata.
For this reason Armoured Legionaires are not included in the list.
Battle formations and tactics
-The army on the move
Foraging was the main source of food for an army, and in Rome 2 one should always put an army in assault mode, to be more historically accurate. Should two armies face each other for longer times, a fortification mode should be set, to allow the player to cover one of the flank with traps and barricades (albeit this is very difficult to achieve against an AI Player).
Armies bigger than one legion (and its auxiliary units) where splintered into three separated parts (center, left and right flanks) giving the command of each part to a single general (that could be a legion commander or an higher-ranked officer, usally a trusted attacheè to the army commander’s staff). Should the enemy be more mobile than the Legions (like the Partians) a square formation was used, having the flanks and the rear fully covered by the legions’ Cohortes, instead of having the units deployed towards the front.
Usually, as soon as the two opposing armies had estabilished contact, they would set the camps a few miles from each other, and every day the two armies would be deployed in good order, ready to fight, awaiting the the enemy to make a move.
The choise of the battlefield was a pivotal decision, since having one flank safe because of the terrain was a step forward to the victory. The main goal of each battle was to brek enemies lines, so that the “piercing” troops could attack the rest of the army from the rear, also breraking enemies morale and preventing them from making an retreat in good order: many battles were resolved by the cavalry’s clashes on the flanks.
In this context cavalry units could be fielded as a whole, choosing one flank where to deploy a main force so that they could be an effective “piercing” hammer while the rest of the infantry was the anvil, triyng to break the enemy’s line-up, or shared between the flanks of the army should both the flank be unguarded.
In the Battle of Pharsalus Ceasar deployed 1000-strong cavalry force on the right flank, being the other flank covered by the river Enipeus and by othere infantry units.
Two Roman Legions in Germany
-Deployment
The battle Formations were usally deep: deploiyng a thin line was useless and dangerous, since the front line soldiers had no support from the rear ranks, and was thus easier for them to run away. Having a deeper formation also helped to keep the first line fully covered of fighters, replacing those killed in battle: ranks spanned from 4-men deep to 10-men and even more (the actual number varying due to the tactical needs of the general and thus varying from battle to battle and from general to general, also varying significantly from time to time): again, in the Battle of Pharsalus, Pompey was forced to deploy his troops into 10-men deep ranks because they were too many, and they were less experienced than Ceasar’s.
Usually more experienced units were deployed in thinner lines (usally 4-men deeep), while new recruits and levies were deployed in deeper ones (6-8 and 10-men deep).
8 men and 4 men deep formations
The Cohortes were deployed in the usual Triplex Acies (triple line) formation (You will have to do it manually, since the actual in-game battle formation doesn’t work with legionnaires-only selections).
Different formation were used when require: Ceasar often employed unusual tactics to ensure the victory, like forming a fourth line behind his cavalry force during the battle of Pharsalus , giving him the victory over the bigger Pompey’s army.
A triplex acies should look like this: (C= Cohort)
C…C…C…C
…C…C…C…
C…C…C…C
Where each line cover the gaps behind and ahead.
A triplex Acies deployment, with 4-men deep Cohorst and skirmisher in the front, the cavalry on the right flank with auxiliary spearmen forming a supporting line behind them.
Should the first 4 Cohortes not being able to defeat the enemy the units behind would charge, while the exhausted and depleted first lines retreated, and so on.
The Cohort system allowed a grater flexibility to the army deloyment, since 10 units were easier to field than 30.
A wise general would choose a good battlefield, with at least one flank covered by some natural environment (like a river or a ravine) or by placing carriages or barricades.
A hill was a very suitable position, especially when defending a position (otherwise it would be a risk that the enemy would not attack).
A Roman Legion (with unit size increased to 320 per unit), in a double line deployment
The legionaries usally charged the enemy (often in silence, shouting during the final sprint), being more effective this way than waiting the enemy arrival, but there could be changes : mantaining the Pharsalus Example, while Ceasar’s (who believed that infantry should always charge the enemy) legionaries were charging Pompey’s line, they realized that the latter had given the order to wait and not to counter charge, so that the enemy would have been forced to run twice the distance to clash againts his line; the more experienced Ceasar’s troops stopped to rest without any order and resumed the charge shortly after.
Usually, when charged by cavalry, a legionary stayed firm and used the pila like a thrusting spear.
The morale was virtually all in a battle (since few of them, practically none, were rersolved by the total destruction of the enemy), and in the legion the eagle was the single most important thing to guard (even before the general). Many battles were lost because of the eagle loss, andy many were won thanks to the bravery on the aquilifer (the eagle’s standard bearer).
Rapid charges followed by retreats was the main tactics for the cavalry units, albeit a huge degree of discipline was required to don’t turn a tactical retreat in an uncontrolled rout.
(This section is still WIP)