Why were the Triarii differently equipped?

[Anthony Ciuni]

During much of the Republican period, the Roman infantry was composed of three infantry lines. The first two, the Hastati and Princeps, were equipped with a short sword (gladius) and pilum. However, the Triarii, the third infantry line, was equipped differently and retained the traditional spear (hastae).

Any thoughts and/or references to primary sources as to why the Triarii were equipped differently?

[Urselius]

One reason is that they were older family men and could afford better quality armour. As for the hasta, I think that it was a better defensive weapon than the pilum. The pilum, being a thrown weapon, was essentially offensive in character. The Triarii were there as a last resort, rem ad Triarios redisse; they had two main functions: to hold off the enemy in order that the Hastati and Principes could rally and reorganise to continue the fight, or to hold off the enemy in order to cover the retreat of the whole army. In either case a thrusting spear was more useful than a javelin.

[Youngster]

Polybius discusses the types of Roman troops in Histories, Chapter 6. I also suspect that the chief reason reason for the different arms is that as senior soldiers the triarii were counted on to hold the line when it was faltering, rather than make the initial assault. Because the enemy already would have closed into combat if the triarii were employed, it makes more sense for them to use a thrusting spear rather than a pilum. Differences in armor can probably be attributed to their greater wealth.

[Corvus]

Maybe the reason for the different armor, is not only the wealth, but also like mentioned here their function to hold the line.
I can imagine that their armor was heavier, and offered more protection.
If I would be a hastati or principes, I would try to use more lighter armor, to be more fast and have more movement

I also think that at some point in roman history, the legionaries got supplied by the state with armor and it was not according to wealth, but to experience and years of service in what of the 3 classes a citizen served

[Antonius Insulae]

The armour used by triarii was not so different than armour used by principes. They wore maille armour (lorica hamata), which is not a light armour. Some (or most) of the hastati couldn't probably afford hamatae, since they were so expensive, so they used pectorales instead (small rectangular or round metal breastplates), but principes and triarii were probably not so differently equipped, other than the obvious difference between a pilum and a hasta. So the armour of triarii offered as much protection as the same armour used by part of the principes too, triarii were not "heavy" soldiers.

All effective armours are heavy, but Romans did have "light troops", called antesignani, who did not wore armour and helmets at all, just a gladius and a small round shield (parma). They were stripped of most of their protective equipment in order to make them fast enough to attack enemy horsemen (both the men and their horses). They were called antesignani ("before standards") since they stood and skirmished in front of the signa (standards of the legion), which were carried in front of the army. Postsignani ("after standards") is a term which was used to refer to all the other soldiers of the army, who were positioned behind their standards.

Romans got uniformed after Gaius Marius, who also changed the custom of soldiers paying their own equipment. After his military reforms men from all social classes could enlist to the army, since they didn't have to have wealth anymore to pay for their gear. Roman legionaries were all equipped similarly at this time, and the old classes of hastati, principes and triarii didn't exist anymore.

[Frank]

As already mentioned, the hasta is the superior weapon for the last line of defense.

The hasta is also the superior weapon against cavalry. Now think about a situation, were the hastati and principes are already engaged in combat and the hostile cavalry manages to flank the legion. Now it must be the Triariis job, to stop them before they can attack the back of the lines. With hastas of course.

In 2nd century AD we see formations were the first 4 lines wear a spear and the last 4 javelins. Makes a lot of sense and increases the flexibility of the unit.

[JaM]

Actually, we have no proof Triarii were armored anyhow differently than Principes or Hastati.. Only thing stated by Polybius was, that those who's wealth was greater than 10000 drachmae, used Mail. Yet, he didnt wrote how many of such citizens were usually in Republican legion. Also, If you look at modern society, you have rich and poor families, as it was in Ancient times. Just because you are young, it doesn't mean you wont be able to afford appropriate equipment if you are member of well suited family. As well as if you are from poorer family, just because you are at prime age, it doenst mean you will be afford better armor. it is completely separate issue not linked with age...

Roman Infantry was divided by age. Young men were Hastati, while Principes were the prime man in their best age. Triarii at the other side were older men, more like reservists, who are no longer in prime strength, therefore they were not used in main battle line, and only engaged when Principes and Hastati got in big troubles. At some battles, Roman Commanders didnt even called triarii to the field, leaving them guarding camp (like for example at Cannae), which is quite important thing - Triarii were not considered to be some kind of an Elite unit, otherwise they would be not left out.. but more like a reservist force.

And why dividing the force like this? it is quite simple - Hastati started battle, because young guys of age around 18+ have best condition. after they got repeled or tired, Principes were engaged while Hastati would reform behind them to support them. General would not send old guys into action if he had any other choice. as those men would get fatigued much faster than younger men. (no offense to older men, i'm also not the youngest,btw)

[Antonius Insulae]

Does anyone know by the way when hastati and principes stopped using hastae themselves, switching to pilum and gladius combo, leaving the spears to triarii?
Roman soldiers at the age of kings all used spears, since they copied the phalanx system from the Greeks of Magna Graecia.
Hastati means "spearmen", principes means "the first men" and the original name of the triarii ("third line of men") was pilani, which also means "spearmen", but from the word 'pilum', not from 'hasta'. Although triarii never used pila as far as we know.
And were the principes originally the first line, since their name would suggest just that? Did the lines get changed, or just the names of the lines...?

[Bryan]

Does anyone know by the way when hastati and principes stopped using hastae themselves, switching to pilum and gladius combo, leaving the spears to triarii?
Roman soldiers at the age of kings all used spears, since they copied the phalanx system from the Greeks of Magna Graecia.
Hastati means "spearmen", principes means "the first men" and the original name of the triarii ("third line of men") was pilani, which also means "spearmen", but from the word 'pilum', not from 'hasta'. Although triarii never used pila as far as we know.
And were the principes originally the first line, since their name would suggest just that? Did the lines get changed, or just the names of the lines...?

I think the name principes more had to do with the age of the men. First men/chief men, as in prime of life, not placement of battle line.

As for replacing the hastus with a pilum it would have taken place sometime after Polybius' histories in the 140s BC but before Caesar's time period nearly 100 years later. Most scholars attribute it as one of Marius' reforms and the abolishment of the property classes. However, I believe it was actually a reform instituted by Q.Caecilius Metellus during Jugurtha's war (Marius was a legate under him). Sallust's works show a clear distinction of Roman military organization, mentioning Roman cohorts for the first time coinciding with the battle of the Muthul River and after, in 109 BC. Personally I think the hasta were replaced with pila because of the nature of the Numidian enemy, nearly all light foot and cavalry skirmishers. Missile weapons were more effective than spears.

[antiochus]

Antonius wrote:
And were the principes originally the first line, since their name would suggest just that?

My research has the principes as being the first line, and eight ranks deep. Therefore, as far as I am concerned, Livy’s comment the earliest Roman formation had been similar to the Macedonian phalanx stands correct.

Antonius wrote:
Did the lines get changed, or just the names of the lines...?

Of those eight ranks, the last two ranks would be classified as the triarii. There are references to the triarii in Livy and Dionysius of the triarii guarding the camp before the introduction of the maniple legion. The maniple legion simply divided the principes from the triarii.

[JaM]

Hastati = those who hurl Hastae..

[Urselius]

I think there is more to the Triarii than just as a sort of last-resort militia. Younger men are fine for a first assault, and can stay in combat longer than older men. However, they are of necessity less experienced than veterans. The Hastati and Principes were used in offence in the earlier stages of a battle, and if they got the upper hand then all was fine. If they were beaten, however, then the virtues of the veterans of the Triarii: experience, steadiness and fighting skills honed by many campaigns came into their own. They had to hold together and fight on in adversity. The same principle was used by the Zulus, the senior regiments (amabutho), composed of older married men, were reserved for the loins of the buffalo-head formation. The head and horns were composed of the younger regiments of unmarried men.

[Bryan]

At the battle of Gabiene, Eumenes' veteran phalanx was made up partially of the Argyraspides (Silver Shields), composed of veterans of Philip and Alexander with the youngest being in his 60s, others in their 80s. They went through their younger opponents like they were nothing. So, I wouldn't necessarily discount age, especially since the Roman Tiari maxed out at 46.

[JaM]

Look at it this way. Let say Hastati were men of age around 18-20. Principes around 25-35, and Triarii older than 35 (just an example)

from this differentiation, it is clear young Hastati will be of completely different quality than older Triarii, they would be faster, would not tired as fast, most likely would be much more effective with throwing javelins (speed, strength, "young bones"). The only advantage Triarii will have is their life experience.. but they would be not very useful in aggressive manner, at least not as Hastati or Principes. With this in mind, defensive use of older men makes sense. They dont need to run around with heavy equipment, while they can be quite useful in defense if needed. plus, very important thing is physical age.. 35 years old man during ancient times would be in much worse physical condition than modern men of the same age.. and imagine 45 years old Triarii facing 18-20 year old Hastati..

[JaM]

At the battle of Gabiene, Eumenes' veteran phalanx was made up partially of the Argyraspides (Silver Shields), composed of veterans of Philip and Alexander with the youngest being in his 60s, others in their 80s. They went through their younger opponents like they were nothing. So, I wouldn't necessarily discount age, especially since the Roman Tiari maxed out at 46.

i would be quite careful believing such old men were really present... average length of life in ancient times was hardly more than 55-60 years or lower.. 80 year old men would be exceptional.. and his physical condition questionable.