Legions vs. Heavy Cavalry

[Aurelian]

This is a historical question; I'm not looking for a lot of conjecture, but for some solid historical information (a little conjecture wouldn't hurt, though). How would post-Marian legionaire infantry fair against heavy cavalry?

First, read Arrian's "Order of Battle Against the Alans" Link (it's short). It shows how a Roman legionary force (with supporting troops) might be deployed to face a heavy cavalry opponent. Simply put: Arrian anchors his flanks with hills and puts his legionaries in an 8 rank deep formation. The first four ranks have heavy thrusting spears, the back four have throwing spears. Archers and ballistae are to the rear to provide extra firepower. If the Alans try to charge down the Romans, Arrian expects them to be thrown back by the weight of missiles the formation can throw, and if necessary tight ranks and thrusting spears. Pursuit is left up to cavalry kept in reserve. Arrian's battle array shows that the Romans could (at least theoretically) put together a tough defensive line to counter heavy cavalry. Note that it doesn't just rely on the legionaires, but rather on a combined arms approach.

A couple of battles against the Parthians provide useful examples of legionaires versus heavy cavalry. Carrhae, as mentioned before, is one. There the Parthian heavy cavalry was forced to wait for openings in the Roman formation before it could be effective. The Parthians feinted charges that would force the Romans to adopt close-order formations, then they would use their horse archers to shoot into the closely packed ranks. The horse archers proved to be a bigger threat at Carrhae than the cataphracts. Of course, the terrain at Carrhae was against the Romans, they weren't well supplied, and the Parthians arranged for an unlimited supply of arrows.

The Romans under Ventidius defeated a later Parthian invasion, and if I recall correctly, legionaires in a good defensive position supported by slingers repelled Parthian cataphracts.

At the battle of Tigranocerta, the Romans used their superior mobility to rout a force of Armenian cataphracts by outflanking them and attacking their relatively unprotected thighs. While not a standard engagement, it is at least one way a Roman force could defeat heavy cavalry.

A few hundred years later, the emperor Julian taught his troops to attack heavily armored Persian cataphracts at a run, dive under their lances, and hamstring the horses. He learned these tactics from the Germans who defeated Julian's own cataphracts in that fashion.

In the 3rd century, Aurelian decided to shield his heavy infantry from a direct charge by Palmyran cataphracts. In two separate battles, he used his light cavalry to draw out and disorder the heavier Palmyrans. When the enemy's cataphracts were disordered and their horses blown, he used light horsemen, Palestinian auxiliaries with heavy clubs, and his other infantry to finish them off.

Even at the beginning of the Dark Ages, infantry (or dismounted cavalry) was quite capable of holding off superior numbers of heavy cavalry. When defeated by the Persians at Callinicum, Belisarius was able to form a small force of infantry and dismounted cavalry that the Persian heavy cavalry wasn't able to touch. They kept close ranks, beat their shields, and yelled, startling the enemy's horses. Narses used his infantry, supported by dismounted Germanic auxiliary cavalry to successfully anchor his battleline against Ostrogothic heavy cavalry. In fact, the Byzantine military manuals claim that the Germanic peoples usually dismounted as a way to fight off enemy cavalry.

So, to sum up, a force of Roman heavy infantry probably had a fairly good chance against heavy cavalry... provided they were arrayed properly. They would try to minimize the impact of a cavalry charge by a tight formation, lots of missiles, beating their shields, and giving the war-cry. They could maneuver to attack the enemy from the flanks, or more likely choose a strong defensive position. Caltrops were available to prepare the field. Full use of combined arms was made.

[Sinner]

Great post by Aurelian, including the key phrase for any infantry of any period when facing heavy cavalry: "provided they were arrayed properly".

Catch a Roman force in marching columns or otherwise unprepared for combat and they will be in deep trouble, perhaps not as much as some infantry since their discipline and good corp of underofficers might enable them to rally and form a defensive line, but they will take more casualties then they would if ready for battle.

Even a homogeneous force of Legionnaires using just their typical equipment and prepared for battle will be difficult for the cavalry to beat. Pila wouldn't be as good as longer, heavier spears for receiving a charge, but they could be used in this role. Even better, the rear ranks could throw their pila a few seconds before the charge hit home, attempting to disrupt the cavalry and thus reduce their impact. Depth of ranks - and the discipline to hold them - would be used to absorb the charge, slowing and halting the cavalry within the Roman lines, unless they can break through or away. The Roman system of shuffling their squads around to reinforce weakened areas of the line will give them a good chance of making sure the cavalry don't push through.

So how to beat them if you're the cavalry? If you have horse archers they might be able to disrupt the Roman lines enough that your heavy horse can successfully charge, providing the Romans in turn don't have their own missile troops. Assuming just heavy cavalry vs Legionnaies, then perhaps a series of small feinted charges with part of the cavalry force, attempting to roll back the Roman defences by getting them to expend their Pila, leaving them more exposed for the main cavalry charge. The problem would be if the Romans hold their nerve & refuse to waste their Pila, or balancing losses among the decoys against the mass of numbers needed to successfully perform the final charge. A better tactic might be to shadow the Romans, waiting for an opportunity to attack, using the horses' greater mobility to range ahead & prepare obstacles, traps and scout for potential ambush sites.

[hotingzilla]

I'd Roman Legionaires will win against heavy cavalry. They have excellent training and are flexible in tactics.

Great posts here!

[KyodaiSteeleye]

testudo - my understanding is that this was a defensive formation against missiles - can't really see that it would have been good against cavalry.

[The_Emperor]

This reminds me of the massive "myth of the cavalry charge" thread we had around when MTW was released. There are some differences between knights and heavy cavalry in ancient times, but I would see legions vs heavy cav as rather like Saxons vs Normans at the battle of Hastings. With a solid mass of disciplined heavy infantry (a shield wall or whatever), I can't see cavalry simply running them down. This is just armchair conjecture - some history buff may tell me (as they did about knights) that horses were trained to charge into spears, but I just don't find that a particularly plausible model of how cavalry fought good heavy infantry.

Actually the battle of Hastings is a very good example of what happens when heavy infantry face cavalry. The Saxons held firm for hours, the Normons did charge but their horses refused when it came to the shield wall.

IIRC the way the Normons won was by hit and run attacks and feigned retreats. Eventually a good part of the Saxon infantry chased them down the hill and broke away from the main army, without their formation they were ridden down and slaughtered.

[TinCow]

While we're discussing this, can someone explain to me why the square is such an effective anti-cavalry formation? This was used from ancient Roman times all the way up to the 19th Century to counter cavalry effectively. Is it simply the fact that there is no flank, or is there something more?

[Sinner]

You've answered it yourself: there is no flank. Infantry need to be face on to cavalry to have any chance of holding them off.