Up until the rise of the Roman Republic, the Greek phalanx was considered the dominant form of military tactics. Evolution had simply favoured longer and longer spears: by the time of Alexander, phalanxes often carried polearms that rivalled a pike in length.

The Kings of Rome appeared to have gone with this prevailing trend. By the time of the early Republic, however, things had changed. Although not the well-organised Legionnaires of popular imagination, the Hastatii, Principes and Triarii of this era tended to favour stabbings swords over spears.

This was the army that was able to secure the basis of the Roman Empire, including a defeat of Macedonia and other states belonging to Alexander's successors which, presumably, were still putting pike phalanxes in the field.

One thing that has never been clear to me is how and why this new military model developed, and whether it was instrumental in defeating Rome's enemies. So:

  • Why did Roman soldiers start to favour swords and maniples over the traditional spear phalanx?
  • Was this new method of waging war a significant factor in their success, or was it more a case of other factors such as good discipline and organisation compared with the relatively chaotic and fragmented post-Alexander world?
  • If so, why did the sword-armed Roman armies enjoy such an advantage over the phalanx?
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    IIRC, early Republican Hastatii and Principes were equipped with only short spears anyway. The Triarii on the other hand kept their spears until Marian, and it was them who formed the Roman equivalent of the Greek phalanx.
    – Semaphore
    Sep 7, 2015 at 11:52
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    One important thing about the roman formations was that they allowed rotation of the front line - as the guys in the front line got tired, they just pulled back and were replaced by fresh guys from behind. The phallanx was extremely effective against light infantry on clear terrain - they were pretty much a shock troop, "heavy cavalry" in a sense. The roman formations could hold their lines pretty much forever, and were a lot better in absorbing losses (killing or severely wounding a guy in the front line of a phallanx is tough, but once he's gone, replacing him is relatively problematic).
    – Luaan
    Sep 8, 2015 at 11:01
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    In the words of arenamaster Gaiden Shinji, "The best techniques are past on by the survivors."
    – corsiKa
    Sep 8, 2015 at 19:36
  • The only history I've read on the subject (which I hope I recall correctly) says the relationship is akin to rock-paper-scissors: that pike-men are good against cavalry, swordsmen against pike-men, and cavalry against unorganized troops. I'm citing Niccolo Machiavelli's The Art of War. (Not to be confused with Sun Tzu's.)
    – Aaron Hall
    Sep 8, 2015 at 20:22
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    Should throw out (pun intended) there that the Pilum was a pretty major device in fighting Phalanxes. The Roman soldier could be out of range of the spears and throw up to 3 Pilum (think of javelin) into the phalanx. Striking a target could be lethal, but even if the Pilum missed a target, it was designed to have the shaft bend and stick into the ground, becoming an obstacle that would interfere with the phalanxes movements as a unit
    – Twelfth
    Jan 24, 2018 at 21:03

7 Answers 7


Actually, the Romans used the same phalanx everyone else did for a very long time. Past Hannibal.

The essence of winning a phalanx battle is to attack the flank of the phalanx. One may achieve that many ways, hence the many ways phalanxes were formed in particular battles - adapted to the width of the battlefield usually, though if one's enemy overdid that, one might go narrow and deep hoping to break them and turn into their new flanks. That kind of calculus.

But ordinarily, the outcome depended upon gaining superiority on one flank or the other in one's mounted forces. I'll use "cavalry" from here, but they were in no way cavalry. Closer to knights in that they fought as individuals. The cavalry that gained superiority then piled in and while slaughtering the hapless foot soldiers, broke the phalanx allowing their own phalanx to complete the main destruction. As everyone fought spear-in-right-hand, a phalanx battle usually turned counterclockwise as if on a pivot making the enemy's right flank the most exposed and therefore an attractive target for trying to gain cavalry superiority.

Side note: elephants were never, ever effective unless held on the flanks for charging into men who were a) distracted by other men trying to kill them, and b) no longer screened by their own knights.

Hence, the spear. To have even the least chance in the world of holding off horsemen, one needs pole arms. Those longer and longer spears one needs of were of no value fighting someone 4-5-6 ranks of men up, but they did allow one to face cavalry. And the most effective method of using a spear in combat is underhanded: ripping up and across; not something one can even attempt with a 23-foot spear. Someone nearby striking over handed at the same man might be handy since he then has to defend up and down, so the 2-3 ranks behind you having slightly longer spears than yours meant they could provide a worthwhile assist.

Spears though are unwieldy - all you really want is the sharp end. Hence the short sword. Why as long/short as it was? Because iron weaponry is brittle, and it couldn't be any longer without a good chance of breaking. Besides, the evolution of the concept started with just using the head of the spear. Bigger shield to hide your strikes and let you concentrate a bit more on the strikes due to its greater protection. A bit less mobile for the larger shield, but one's striking was far more aggressive, able to come from almost any place and direction. Not as effective anymore though against horse from the flanks, but if you can beat the enemy phalanx before his horse gains superiority on a flank, that never matters.

So the maniple. It allows easier maintenance of your line when attacking over broken ground, so your enemy sees his more broken by the ground than you see yours. (Men can speed up or slow down because there aren't 7-49 men directly behind you (picture cars starting up from a traffic light and one driver hits his brakes for even a moment), and they can move up a rank or two if the ground causes a gap to form while the men farther behind can edge over and up to keep the depth uniform. In a phalanx, the men moving about have the wrong weaponry.

Perhaps far more important, picture a man in the first rank getting tired. He just gets more tired until he is killed in the phalanx. The men behind him have completely unsuitable spears for first rank fighting. A man from rank 7 is going to replace him using his 23-foot spear?? There is weapon trading happening as they rotate out?? Not too easy. With the maniple, not only can men move up to rotate out tired fighters, but they can rotate into any role in the entire unit. They form a reserve of ready, rested replacements and use them as needed. (In fact, the concept of a reserve for the overall army may have been born in the maniple. Though it took a while for the Romans to learn how to use reserves properly.)

Oh, and wounded men can be rotated fairly easily and actually live through the battle, perhaps even fight more later on.

As to facing cavalry if/when the enemy gained tactical superiority on a flank, they still had supplies of javelins and actual spears. Though the truth is, no foot unit survives when an intact unit of heavily armored and weaponed knights piles into your formation from the flank.

To make it very short, why fight using the whole heavy spear when all you really want is the short, sharp end? The Romans found they had no answer to that and used just the short, sharp end of the spear. What we call a short sword.

  • Fascinating. I had assumed the evolution of spear length was to allow more and more ranks to fight, but the logic presented here makes rather more sense.
    – Bob Tway
    Sep 8, 2015 at 11:43
  • "To have the least chance" I think you mean "To have at least a chance".
    – ThomasW
    Sep 9, 2015 at 1:58
  • I think Lancer fits better than knight in this historical context, a knight implies more than the military unit, where as a lancer is better fitting for a spear mounted flanking cavalry unit (that was common among Greek Armies) Sep 9, 2015 at 5:22
  • Comment only AND I know you know this AND not the millenium or weapons systems you had in mind, :-), but -> " ...no foot unit survives when an intact unit of heavily armored and weaponed knights piles into your formation from the flank." -> At Agincourt they managed fairly well to have no "side" (as per your comments above) and survived against well armoured "well enough" (although there were many other factors (incl LB & clothyard shaft and much more) ), and .... Sep 9, 2015 at 11:00
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    @JustAnotherDotNetDev: Actually, knight is closer in many ways. They were the wealthier citizens, had full armor, charged together, but with no discipline: like medieval knights would attempt to pull ahead. No unit awareness, cohesion, or attempt to maintain any formation once their fighting began. Like knights, commanders had no influence over them ("fire and forget") once launched. As with knights, their enthusiasm for the chase often carried them miles away when still needed. Lancers are "cavalry." Usually not at all wealthy, maintain discipline, and will withdraw and re-form as commanded.
    – Roy
    Sep 10, 2015 at 3:59

The Romans were very good in copying tactics and equipment from other peoples. They learned the Phalanx from the Etruscans. The phalanx works like a wall: difficult to get through, but also almost impossible to maneuver. When the Romans met their new enemies the Samnites, a people from the mountains, they saw that the Samnites were armed with long shields and javelins. The short round roman shield gave little protection against the projectiles. Moreover the Samnites operated in much smaller unites than the inflexible phalanx. The first battles against the Samnites weren't a success for the Romans, but the Romans adapted and in the end (after 3 wars) the Romans subdued the Samnites. The Greek author Polybius gives in his Histories 18.28 a nice comparison between the two different tactics Look here: http://www.the-romans.eu/books/Polybius-histories-18.php#28. The gladius the famous Spanish short sword was later adopted. Later in the imperial period probably when the quality of the steel had improved they would return to the longer sword


As I remember, the biggest problems of phalanx were slow pace and inability to operate on a rough terrain (consider the length of their spears). In the battle of Pydna the macedonians had early success yet the romans were able to regroup and won the battle in the later counter-attack.

So the phalanx was pretty good for one-time onslaught but in an advanced maneuver fighting it totally lacked the skills of the roman legion.

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    I think that this might be due to the fact that the phalanx as it originated in the incessant internecine warfare of the Greek city states was a very singular affair: two phalanxes "pushed and heaved" against each other till one broke. (Victor Davis Hanson's earl book is good on this) Sep 7, 2015 at 13:29
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    The original Greek city-state phalanx warfare was in a sense highly formalized (two similar formations push against each other till one breaks; see Victor Davis Hanson's Warfare and Agriculture in Classical Greece for this). On the other hand, Alexander used the phalanx to hold the opponent while his cavalry (led by him in person, usually) drove through the enemy's flank and broke his formation. In both cases, the phalanx was used a special-purpose tool, not a general-purpose one. When it faced a more flexible general-purpose formation as the mature legion, it lost. Just my 2 cents. Sep 7, 2015 at 13:33
  • @FelixGoldberg Well, yes. But greek phalanx was quite successful against persians even before the macedonian "super-phalanx". So it was not so bad for many years. It took some time to develop the better formation. Say, Pyrrhus still was doing OK against legions. BTW. "Mature" legion should usually stand for "post-Marius" legion. But romans beat macedonians even earlier.
    – Matt
    Sep 7, 2015 at 14:30
  • I used "mature" as a (poorly chosen) colloquialism for "manipular". Sep 8, 2015 at 12:06
  • The Roman legion gained flexibility and the ability to work on uneven ground the hard way through drubbings by the Samnites in their centuries of warfare with them down to the Social War (350-90 bc). It was this edge that let them dice up the Macedonian and Successor Phalanx. The adoption of the Spanish sword sometime after the Punic Wars just helped things out.
    – Oldcat
    Sep 9, 2015 at 0:42

Referring to the documentary series "Conquest" of history channel may be a bit too much on the popular side of popular-science but I think they have a point (or rather some). From what I remember they said:

  • shields grew in size
    • allowing to push into rows of spears and lock them between the shields while staying unhurt
    • and weight, compensating the increase in weight with a reduction in weight of the weapon keeps the total weight balance
  • short stabbing swords
    • allow for multiple stabs in the same amount of time
    • are hard to see coming when operated from behind a full sized shield

So the answer boils down to: They found the combination of short sword and big shield to work well for their use case.

How significant this advantageous combination contributed to their success is highly speculative. Probably it would not have been as effective, if the formation was set up from less trained and/or motivated soldiers.
Part of the tactic described above is walking forward right into a line of spears, right?

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    The original hoplite sheld was large, if not as large as the Roman cylindrical spear. The Macedonians discarded this shield in favor of a large two handed spear to outrange the hoplite phalanx.
    – Oldcat
    Sep 9, 2015 at 0:47

Because the Roman infantry developed a "two wave" attack structure.

The phalanxes used long spears, whose advantage was that they could kill enemies at "long range" (15-20 feet).

So the Romans broke up their attack into two stages. The first part was with "pilum" (throwing spears), which were launched from 50-60 feet away, and had a greater range than long spears, plus momentum. Put another way, the Romans had the advantage of drawing the "first blood."

The the second part of the attack was "close up" with thrusting swords. These were shorter than spears but had the advantage of being more maneuverable. Their main disadvantage against spears was that an array of long spears could hold off a sword attack. But this array was broken up by the pilum attack, giving the greater maneuverability of swords a decisive advantage.


Because they had more metal. A phalanx was useful when metal was more rare and expensive, since the only metal you need is that for the tip of the spear. A phalanx is a relatively simple structure. You have the phalanx itself, then a cavalry to protect its weakspots.

The Romans, due to advances in metallurgy and mining had much more metal to work with. They developed weapons such as the pilum, metal rimmed shields, and the steel gladius, all requiring a lot of metal. These weapons were effective, especially in small scale battles and police actions. The Roman system was not necessarily superior to the phalanx (for example, the Romans lost the Battle of Heraclea against a phalanx), but was more suited to the cheaper cost of metal as time went on.

Another factor is that the gladius emphasized the advantage of steel. A steel spear point is only moderately better than a bronze spear point, but a steel sword is much better than a bronze sword. Since most of their opponents were equipped with bronze weapons, the Romans could maximize the effect of their possession of steel by using swords.

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    "a steel sword is much better than a bronze sword" - is this correct? if memory serves from back when I was reading about metallurgy, the most meaningful difference between bronze and iron ages was that for bronze you needed two sources of metal vs a single one (and greater heat) for iron. besides that, the two were mostly equivalent, with only a slight advantage for iron. steel is arguably stronger, but was Roman steel (which it was not, since they imported it if I recall correctly) that stronger? Jul 13, 2016 at 0:02

Pilum were excellent to harass and break up formations opposing Roman forces, that's true enough. Additionally, the following ranks were able to use pilum to assist the first rank which were fighting.

However, I think the evolution of the Roman legion to be composed of pilum, huge shield, and short stabbing sword was to be a hard counter against SPEARS which were the king of the battlefield. The training and discipline of the Roman soldiers led to victory oftentimes, coupled with their diet and superior equipment against others similarly armed.

Spears win nearly every hand to hand encounter. The only way a swordsman can win against a spear is with the addition of a large shield and then to close range quickly. Thus, the gladius was superior in that role.

Stabbing swords allow fewer openings to counterattack, their wielders better balance, and take less energy to use. Never forget the role of fatigue in a fight.

Who has not wrestled or boxed? Just a very short time leads to utter exhaustion, much less hacking at an enemy with a sword, axe, or mace.

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