Legion VS Phalanx – How the Roman Army Defeated the Phalanx

The phalanx was one of the most effective formations in Antiquity and was used from the Greco-Persian Wars to the invasion of Alexander the Great into the Persian Empire and also by all of Alexanders’ successors in their fight for control over Alexanders’ empire.

But despite that successful history, the phalanx proved inferior to the Roman army. So in the following, I would like to present how the Roman army was able to defeat the phalanx.

The manipular legion in which maniples of 120 men operated independently from each other was highly flexible and proved superior to the rigid phalanx that had to deploy and fight in one continuous line. While the 15-21 ft long pikes used by the Macedonian phalanx were effective at a distance, they proved useless in close combat. So Roman soldiers used their large shields to push up the long pikes and rush into close combat where their armament proved superior to the armament of the phalangites. As soon as the phalanx had lost its cohesion it became vulnerable and could be broken by the Roman troops.

Let`s take a closer look.

Legion vs Phalanx – advantages and disadvantages of both systems

Before we can look at how exactly the Roman army was able to defeat a phalanx in battle we first have to take a look at the differences between the Roman manipular army and the phalanx. Both systems had their advantages and downsides.

So let`s start by looking at the phalanx.

The advantages & disadvantages of the phalanx

At the time Rome turned its attention eastwards the original Greek phalanx, more on that formation here, had already been improved. So Rome had to face the Macedonian phalanx, a system that had been introduced by the father of Alexander the Great and was used by both Alexander as well as his successors who fought over Alexander’s empire to great effect.

Just like the original Greek phalanx the Macedonian phalanx operated in a tight formation and as one consecutive line of battle. However, unlike the Greek Hoplites, the Macedonian phalangites used the sarissa, a pike that measured 15-21 ft making it much longer than the spear that was used in the Greek phalanx.

For more information on the Macedonian phalanx, how many rows of men one phalanx had, how it was best used in battle, and why the flanks were extremely vulnerable I would like to recommend you my article here. There you can also find out more about the disadvantages that were shared by both the Greek and the Macedonian phalanx.

Because of that, I will now only briefly talk about the disadvantages of the phalanx.

A phalanx was best used to put head-on pressure on the opposing formation. But to be effective that phalanx had to be both tightly packed and maneuver (and fight) in one continuous line. That made both the Greek and the Macedonian phalanx quite rigid, inflexible, and as such unsuitable for fighting in rugged terrain.

Additionally, it is also important to state that while the long pikes of the Macedonian phalangites gave them a longer reach, the Kopis that the phalangites used as a secondary weapon in combination with their small round shields made them less effective in close combat.

Do you want to find out more about the Kopis, how it was best used and what other type of sword was used by the Greeks? Then check out my article here.

So as soon as an enemy had made it cross the points of the pikes and into close combat the phalangites were at a massive disadvantage to troops more suited for close combat.

Troops like for example the Roman Hastati and Principes for example.

Why was the Roman army superior to the Phalanx ?

So we just found out that the disadvantages of the Macedonian phalanx were its rigidity, inflexibility, and its need to deploy in one continuous line which made it unsuitable for fighting on rugged terrain.

The Roman army on the other hand had turned into the exact opposite since Rome had reformed its army and had abandoned the use of the phalanx during the Second Samnite War.

Here you can find out more about why Rome abandoned fighting in the phalanx formation and when Rome had originally adopted the phalanx formation.

The manipular system that Rome adopted after it had abandoned the use of the phalanx was the exact opposite of the Macedonian phalanx. It was highly flexible and as such ideal for fighting even on rugged terrain.

Unlike the Macedonian phalanx, the Roman army was organized into maniples of 120 men each that could operate independently under the umbrella of the Legion.

Since these maniples were independent of each other the Roman army – unlike the Macedonian phalanx –  did not have to maintain one continuous line. Instead, the maniples combined with the tactical freedoms that the centurions, officers commanding the maniples, had allowed for a much more flexible and adaptable type of warfare.

The special role of the centurions is actually one of the 5 reasons for the success of the Roman army. Here you can find my article with more information on that and also the other 4 reasons that made the Roman army so successful.

But let`s now look at how the Roman army did it!

How did the Roman army defeat a phalanx formation?

Before we can look at how the Roman soldier defeated the phalanx we first have to look at how both formations would deploy.

Preliminary remarks on equipment and battle formation of both the Roman legion and the Macedonian phalanx

Let`s start with both the Roman army and the Macedonian phalanx taking positions on the battlefield. While the phalanx had to form one continuous line with a depth of usually 16 men, its vulnerable flanks were covered by more mobile and flexible cavalry or infantry.

The Roman army deployed in 3 lines with skirmishers (so-called Velites) operating in front of the first Roman line.

Each line was made up of one type of Roman infantry, the first line by the Hastati, the second by the Principes, and the last line by the Triarii. For more information on the differences in armament and age of these 3 groups, you might want to check out my article here.

The first two lines of battle, the 10 maniples of Hastati in the first and the 10 maniples of Principes in the second, are the most important for us to look at. These two lines were deployed in a checkerboard system while the third line, the Triarii, formed one continuous line.

Here you can find out more about the role of the Triarii and why they were the only line that formed a continuous line.

Both the Hastati and Principes were armed with 2 javelins, a large shield that covered them from knee to chin, and a Gladius (short-sword). The only difference between them was that the Hastati didn`t wear shirts of chainmail and were younger and less experienced. Apart from that, they fought exactly the same in the following I will talk about both of them.

Please also note that the Principes in the second line of battle would only engage after the Hastati that made up the first line of battle had failed to break the enemy and had retreated through the gaps between the maniples of the second line of battle.

For more information on the interaction between the 3 lines of battle, you can check out my article here.

But enough of the preliminary remarks, let`s look at how a Roman army fought against a Macedonian phalanx.

How did the Roman legion defeat a phalanx?

While the Macedonian phalanx would advance over flat ground in one continuous line the first Romans to engage were the Velites, skirmishers who carried 7 light javelins.

These Velites would throw their javelins at the phalanx.

And while most of the javelins were deflected by either the small round shields that the phalangites had attached to their left underarm or the pikes the phalangites in the rear rows pointed towards the sky, some still found their target.

By the way, the reason why the phalangites in the rear pointed their pikes towards the sky had to do with the depth of the Macedonian phalanx. While the phalanx was usually 16 rows deep only the first 5-6 rows could engage the enemy with their pikes.

As soon as the Velites had thrown their 7 javelins (and had inflicted first casualties in the Macedonian phalanx) they retreated and left the field to the 10 maniples of Hastati in the first Roman line of battle.

The Hastati would advance and then throw their 2 javelins in two closely followed volleys. Here you can find out more about the distance at which these volleys were thrown and the general fighting style of both Hastati and Principes.

Ok, so now we have the situation that the javelins that both Velites and Hastati had thrown had inflicted the first casualties on the phalangites. Now the Romans no longer had their javelins but had to draw their swords to engage.

The Romans with their swords now had to overcome a wall of pikes pointed at them.

And while that at first proved almost impossible to overcome the Romans had learned until the battle of Asculum in 280 BC that the pikes of the Macedonian phalangites became completely useless as soon as one came into close combat. There the phalangites with their small round shields were inferior to the Roman soldiers with their large rectangular shields that covered them from chin to knee.

The only problem was getting past the points of the wall of pikes that the first 5-6 rows within a phalanx pointed at the Roman soldiers.

To get past the heads of the long sarissa of the Macedonian phalangites the Romans used the scutum (their large shields) to push the points of the pikes up and then rush under them into close combat where the Roman armament proved superior to the armament of the phalangites.

Here you can find out more about the armament of the Roman soldiers while my article here talks about the armament of the Macedonian phalangites.

As soon as the first Roman soldiers had managed to break into the phalanx that had already been weakened by the javelins it was up to the centurions to exploit opportunities by maneuvering their maniples into the opening gaps of the phalanx. Widening these gaps then resulted in the loss of cohesion of the phalanx. And that meant defeat.

By the way, the case that a phalanx lost its cohesion did not only mean a defeat but also a much higher casualty rate. For more information on that and the average casualty rates of phalanx warfare, you can check out my article here.

In case the Hastati, the first line of battle, were not able to get past the pikes of the phalangites they retreated behind the Principes so that the more experienced and better-armored men could have a go at it. For more information on that, I would like to recommend you my article here.

Ok, so that is how a Roman legion would break a phalanx in theory.

However, I think it might also be a good idea to show an actual example of a battle where the flexibility of the Roman manipular legion overcame the rigidity of the phalanx (although the ground played a major role) in the end.

So let`s now briefly look at the Battle of Pydna.

The Battle of Pydna (168 BC): A victory of the flexible Roman army over the rigid Macedonian phalanx

The Battle of Pydna is oftentimes seen as a prime example of the advantages of the more flexible Roman legion over the rigid Macedonian phalanx.

While during the first phase of the battle the Roman soldiers proved unable to get past the wall of pikes the Macedonian phalanx pointed at them that changed as the Roman troops fell back. That retreat had been planned from the beginning and had the goal of pulling the Macedonian phalanx away from the flat battlefield and onto the rugged foothills.

The high flexibility of the Manipular legion allowed the Romans to retreat over rugged terrain without reducing their fighting value while the following phalanx had its problems. The rugged terrain caused the phalanx to lose its cohesion which was absolutely crucial for its success. As planned the gaps that were opening in the now vulnerable Macedonian phalanx were exploited by the centurions who led their men right into these gaps. That caused the phalanx to break and won Rome the Battle of Pydna.

So there we have it, that is how Rome was able to overcome a formation as tested and effective as the phalanx.

I hope you enjoyed our trip into Antiquity. In case you haven`t got enough of ancient Rome yet I would like to recommend you my article here talking about the diets of Roman soldiers.

And here you can find out more about the price of salt and whether or not salt was really worth its weight in gold.

Take care of yourself because you deserve it. You really do.

Until next time

Yours truly

Luke Reitzer


Johannes Kromayer: Heerwesen und Kriegsführung der Griechen und Römer (München 1963).

Robert M. Ogilvie: Das frühe Rom und die Etrusker (1983 München).