From my limited understanding of ancient warfare, having a spearwall in the front was a tried and true tactic that not only excelled in repelling both mounted enemies and those on foot, but also in preserving the lives of one's own soldiers. Why did the Roman's decide to leave their heavy spear using Triarii in the back and give the men in the front swords? Then later, why did they seem to drop spears for melee purposes altogether?
EDIT: Thanks for the responses everyone. There's certainly been a lot more light shed on this issue than was previously for me, but I still don't have a very clear answer in my head.
"Romans adopted swords to combat the Samnites due to terrain making spear use unwieldy." As SofNascimento pointed out, Greece was pretty mountainous as well, yet they employed the phalanx to great effect. Also, why did the Romans stick to the sword strategy after the Samnites had been subjugated?
"Spears were too unwieldy, swords allowed for better maneuverability and efficacy when flanking." I can believe that the sword was better for that purpose, but I'm having trouble imagining a line of swords and a line of spears facing off and the swords ending up on the winning end. Why didn't they have the legionary equipped with a spear and give him a sword as a side arm for the occasion it becomes more practical than the spear? Or why not let auxiliary units worry about being more maneuverable and flanky panky while keeping the legionary in a safe, defensive, and solid spearwall?
"It wasn't just the sword, it was also the pilum." The effectiveness of the pilum is irrefutable, but then why not just use the spear AND the pilum? That way you could disrupt enemy lines, AND stay safe behind the length of the spear. I don't think the legionary's heavy armor and large shield allowed for him to make a mad charge at the enemy after unleashing a wave of pila anyway. Unless it did.(?)
"The pilum and other throwing weapons were also used as thrusting weapons." While being one of the more satisfying answers for me, I still find it a little dubious. Unfortunately I suppose there's no way of knowing for sure whether or not the pilum's construction allowed it to stand up to the abuse of using it as a thrusting weapon. I've frequently heard they were designed to break upon contact to disallow enemy usage. But even assuming they could be used reliably as a thrusting weapon, it still seems to me that a polearm designed to be used as a thrusting weapon to begin with would have been utilized if the need for thrusting weapons was seen.
"Though the image of the legionary with a gladius is the standard, they very likely used other weapons too." I also believe this to be very likely, but if this were so, if the gladius wielding legionary was the standard, that would mean that the gladius was the most frequently used. To my knowledge, the sword was almost always perceived and used as a sidearm. Even the katana was usually set aside in favor of the spear on the battlefield (could be wrong here too) in Japan, despite what the movies and ultimate-weapon-katana fanboys will tell you. If the Roman legions utilized a wide variety of weapons in different situations, I think it'd be safe to assume the spear would have been the most commonly used, as it was throughout the rest of the world.
"Rome's discipline and professionalism was truly its main weapon." I can believe that superior training could allow for effective use of the sword against the spear, but I also believe that superior training with the spear would beat superior training with the sword. With the exception of flanking maneuvers, I thought the spear would almost always come out on top, an issue that could be remedied with employment of swords as sidearms, or even units suitably armed defending the flanks for such occasions. Is there some advantage the sword held over the spear in a face-to-face engagement that I hadn't thought of?
Really, I'm just confused why the Roman's primary weapon became the sword, and how they managed to make it work for them. Polearms were used by pretty much every society as a primary battlefield weapon up until the invention and widespread usage of the firearm, and even then it was still technically used. The bayonet on a rifle could be loosely interpreted as a polearm of sorts. To my knowledge, Rome was the only society I can think of that broke this trend and got away with it.
While the claim is often made that the Romans abandoned the use of the spear in favor of the sword, I don't think the literary tradition supports that at all. No author tells us that Roman armies didn't use their javelins for thrusting. In fact, Caesar notes that at Alesia his troops "omissis pilis gladiis rem gerunt" (with their javelins set down they pressed the attack with their swords). The implication here is that Caesar's men were using their javelins as pikes, which is how that passage is sometimes translated, with pike in the place of javelin. Plutarch famously describes Caesar's men at Pharsalus jabbing upwards at the faces of Pompey's cavalry with their javelins. Arrian describes his legionaries in the Ἔκταξις κατὰ Ἀλανών as using some sort of spear in close formation--it's a bit unclear what Arrian is talking about, whether they're the troops' javelins, or pikes or what, but obviously they're spears of some kind being used for thrusting
EDIT: From your edit, it seems to me that you're thinking of warfare as some sort of rock-paper-scissors formula, which is nonsense. In particular this comment:
With the exception of flanking maneuvers, I thought the spear would almost always come out on top, an issue that could be remedied with employment of swords as sidearms, or even units suitably armed defending the flanks for such occasions
very much suggests to me that you're thinking of this as some sort of Total War-esque formula, particularly since in the Total War games sword infantry is traditionally used in flanking maneuvers while spear infantry hold the line. A lot of posts have been written about all the reasons why that's a nonsensical idea (and it's certainly not something borne out in our textual corpus), so I won't attempt to rephrase what has been said many times already, especially as I'm not a military historian--just search "spears" or "spearmen" in the search function and you'll find dozens of threads about this sort of thing. The short version is that while that sort of thing works really great in a video game, it's just not the way real life works
It is often attributed to the Samnite Wars (mid 4th - early 3rd C BCE) when Rome began fighting in the hilly highland terrain. Previous conflicts had been in the flatter Etruria and Latium which was better suited to the hoplite phalanx. The manipular army was more maneuverable and the multiple lines offered more tactical flexibility.
The combination of pila and swords must have been effective since the ever-practical Romans stuck to the combination - the first confrontation between a pike phalanx and the manipular legion at Heraclea resulted in a tactical stalemate (in the end the battle was decided by Pyrrhus' elephants defeating the Roman cavalry triggering a rout of the legions).
As for mounted enemies, Rome's early opponents had little cavalry and I'd say it wasn't until the Punic Wars that they began to face enemies with dangerous cavalry forces. But cavalry was traditionally placed on the wings where it would face their opponent's cavalry. With ancient cavalry, mounted charges at infantry were uncommon.
Thanks for the answers so far everyone.
So is it just ignorant of me to believe that overall, the spear was the best melee weapon in most situations at the time? I was under the impression that whether it be one on one, or army against army, spears typically held the advantage in head on clashes.
The theory in my head was that Rome's superior discipline and dedicated soldiers compensated for any kind of equipment disadvantage. I knew the pilum was extremely effective in disrupting enemy lines, but I always wondered why they didn't just use dedicated melee spears in addition to pilum.
This is the first I'm hearing of the use of pilum and javelins as melee weapons. I definitely don't doubt it, going to have to look into that more.
Well for one, the manipular legion is a whole lot more maneuverable than a Greek or Macedonian style phalanx. If you manage to flank the enemy's main battle line and they have no local reserves to counter you, they're pretty much toast. Wielding a sword (notably the Gladius) is easier than using a spear for such a maneuver, where your infantry needs to carve out a part of the enemy's line before they can reform to face the new threat. A volley of pila also serves as a great tool to break up an enemy's formation at the critical moment, be it receiving a charge or conducting one.
One most also take into account Rome's enemies. The hilly tribes of central Italy didn't field much cavalry, and why form dedicated spear units to counter Gallic or Iberian cavalry if you could just use your Latin allies or other auxiliaries to take care of them? As time progressed however, and the Empire was faced with the nomad peoples of the Middle East and eventual migrations of Germanic peoples, many of the units in the army reverted to using spears. It took less time to train someone to use it, could be manufactured faster, and didn't need as much upkeep. Indeed, spearwalls became the most common type of tactic used by later Roman and early Medieval armies, notably because they lacked experience and had fewer and fewer professionals.
Of course all these changes didn't occur overnight, and the early republican Roman army retained some vestiges of hoplite warfare, notably it's militia type characteristics where men provide their own weapons based on wealth and social status. During the 3rd century BC, most infantry actually continued using the spear: hastae (hastati) means spearman after all. Yet the organizational structure was changed from the Greek style hoplite battle line to the manipular one, with the well known classes of troops (Velites, Hastati, Principes, Triarii, Roraii and equites) who could respond to changes on the battlefield faster than their counterparts. Any lessons learned from serious crises such as the second Punic war (Having better cavalry, for example) were incorporated into the Roman army, who used what best suited it's purpose at the time.
Hope that answered your question!
Sources:
-The Roman army, the Greatest war machine of the ancient world (Chris McNab)
-The Roman art of war under the Republic (F.E Adcock)
Assuming that the romans did drop spear use, how effective would cavalry actually be against the roman formations?