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Legion Composition Guide

By Le Gorgo Ramsi

This guide explains the ideal composition for a legion in single player, and some build ideas for multiplayer.

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Le Gorgo Ramsi
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Category: Gameplay Basics, Multiplayer

Languages: English

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Updated

15 Apr, 2022 @ 4:26pm

4 Mar, 2023 @ 11:06am

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Overview

Ideal Single Player Legion (SPL)

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Ideal Single Player Legion (SPL)

The ideal legion in a single player game is quite simple; you'll want to have comprised mainly of heavy infantry, heavy cavalry, and horse archers (if you can't get horse archers just use cavalry).

Most terrain is restricted to a certain combat width, with the lowest being 16 and the highest being 40. With that in mind you'll want to structure your legion around this. Another important unit are engineers, you'll want at least 10% of your legion to be engineers, because if you have one engineer cohort for every 10 other cohorts in your army you will take no river crossing penalties. With this in mind the size of our legions now have a minimum size, and a maximum size.

Now, for our composition we need to keep one more thing in mind; there are three organized parts to your legion, flanking units, primary units, and secondary units. Flanking units will always be to the far left, and right of the battle, they use their high flanking range (mobility) to deal damage to other units, this is where we'll put our cavalry archers. The flank can also have a set size, which determines how many cohorts will be there (max), with this in mind it's a good idea to minimize the size of your flanks to 5, size 5 means that up to ten cohorts will be flanking at a time. Primary units are always forced to the middle of the battle no matter what, here we put our heavy cavalry we'll want 16 cohorts of heavy cavalry, because they are expensive, and past that they become obsolete. Secondary cohorts are forced as close to the middle as possible (behind the primary cohorts), therefore these units are our canon fodder, they will fill the line, and reinforce any unit that falls.

With all that said we can make the ideal legion, 16 cohorts of heavy cavalry as primary position,6 cohorts of horse archers* as flankers (size 5), then we'll want 18 cohorts of heavy infantry as secondary units, finally we'll want 5 units of engineers, and 5 units of supply trains; this legion will be 25 thousand units strong and ideal for the maximum terrain defense, but also operational for other terrain defenses.

*You only want 6 Regiments of horse archers so that you force the game to put only 3 units in each Flank.

15 Comments

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Rambosfire 8 Nov @ 7:32pm

@it's me and anyone else interested, no this guide does not work with the Invictus mod in many ways. Namely in the unit modifiers, especially the flanking units, and the fact it adds spear infantry, which historically was more dominant in the days of the Phalanx and before Rome underwent the Marian reforms and still used the Polybian Maniupular structure.

This means is that Spears are a hard counter to the frontal Heavy Cav charge in this guide, with a +20% unit mod. against. If the Phalanx tactic is used from the Greek Poleis Traditions, then in Invictus it adds a 100% unit effectiveness to Spears as well. Yikes... Pikes. Basically before your heavy inf gets buffed, you're still incentivised to use Spears in case of Cav due to modifiers Cav get against H.Inf

There's more intricacy to discuss the nuances of combat changes in Invictus, but with a 1000 word cap it's hard to get into here. I suggest checking out the Invictus Imp.Rom. wiki page, or i might write a guide about it.

Le Gorgo Ramsi [author] 28 Mar @ 2:48pm

@it’s me, the guide was not made with Invictus, but I’m not aware of any fundamental military differences in the mod (other that the extra unit). The build should still crush any AI army you come across.

it's me 27 Mar @ 2:14pm

Does this work for invictus also?

Le Gorgo Ramsi [author] 26 Mar @ 11:55am

@RocketMan, any more than that will not be deployed at the start of battle, the heavy cavalry is there to mulch the enemy frontline for the heavy infantry. You can put more heavy cavalry into the legion the cost effectiveness of the legion goes down significantly.

Additionally if you stack more than one full stack of a legion for a larger battle (which is when you would want the additional heavy cavalry) the cavalry from the other stacks would reinforce before the heavy infantry. This works because the legion is designed to fit in all terrain types. (Stacking this legion does make the flanks larger, and the flanking units are not very powerful, so I would recommend lowering the flank size if you plan on combining several stacks).

RocketMan 17 Mar @ 6:01pm

"we'll want 16 cohorts of heavy cavalry, because they are expensive, and past that they become obsolete." Why do heavy cavalry become obsolete after 16 cohorts?

Le Gorgo Ramsi [author] 29 Apr, 2023 @ 3:24pm

@zen with legions you get mil tradition with every battle/seige, the only reason you should get a legion ASAP is if you don't have money or manpower. Mercs don't get the special legion bonuses. Also levies are horrible because you constantly bleed pops which is a drain on long term scaling.

zen 25 Apr, 2023 @ 6:17am

What boosts don't your mercs get? I always thought they got everything a levy got.
But how soon should one create a legion? I kind of like to use my levies to farm for military traditions in the first 150 years, am I missing out by waiting so long to create a legion?

Le Gorgo Ramsi [author] 9 Apr, 2023 @ 10:33am

@iogilvie I usually just make a small (~15k) legion for assaults composed entirely of supply chains and light infantry. Assaulting gives you diminishing returns for every single soldier assaulting so I would split the legion mid war to assault forts. 15k is about enough to assault 5 forts within a very short time frame.

Also this legion is assuming that you can afford it (legions also don't use pops, they use manpower). It's main purpose is destroying the levies the enemy. The only thing that really counters it is elephants (they're supper expensive though so the AI will never mass build them).

Mercs are bad because they don't get all your ideas/tech boosts. Mercs are also super expensive, and you can only have like 5 merc stacks max. I do use all 5 though...

Scorpioneldar 4 Apr, 2023 @ 10:52am

Thanks for editiing it. I was pretty confused by size 3 flanks. These seem like pretty expensive legions If you have the cash for these isn't hiring mercs better as you don't lose pops when they die? major drawback of mercs is cost but these legions would likely be much more expensive to maintain. and it seems terrible for sieges. Typically I like to seige with my legions (as they have the commanders and engineers for it.) though I suppose you could make a legion up like this. then throw say 10k Light Infantry and 1 engineers in afterwords and split them off from the main force.

Le Gorgo Ramsi [author] 4 Mar, 2023 @ 11:14am

@iogilvie, and @sad_mofo, sorry for the confusion, size 3 doesn't exist, you can actually use any flank size other than 2, because we only want 6 flanking units to optimize combat width. The game will automatically push primary, or secondary units into the open spaces. This Legion composition is trying to fit in every kind of terrain in the game, so the 6 flanking units allows it to be effective in every terrain type. The only terrain this Legion doesn't fit into effectively is farmland, but stacking 2 legions should make it fit better (more flanking units, and more heavy cavalry). Thank you for pointing out that typo, I edited the guide to be more accurate, and hopefully more clear.

PS: if you had read the whole guide you would've noted that you only use 6 regiments of horse archers.

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