According to
Pat Southern,
principes appear to have been born from remnants of the old second class of the army under the
Etruscan kings when it was reformed by
Marcus Furius Camillus. The second class stood in some of the first few ranks of a very large
phalanx and were equipped in a similar manner to
principes. They would support the heavier first class in the front ranks. It is probable that engagements with the
Samnites and a crushing defeat at the hands of the
Gallic warlord
Brennus, who both used many smaller military units rather than a few very large ones, taught the Romans the importance of flexibility and the inadequacy of the phalanx on the rough, hilly ground of central Italy.
Fourth and third centuries BC In the late 4th and early 3rd centuries BC, men were sorted into classes based on wealth, the
principes being the wealthiest after the
triarii.
Principes were armed with a
pilum, which is a throwing spear, and a sword, which was used after the spear had been thrown. They fought in a
quincunx formation, usually carrying
scuta, large rectangular shields, and bronze
helmets, often with a number of feathers fixed onto the top to increase stature. They wore heavier armour types, the most common form being
chainmail, which offered a good degree of protection without hindering movement. The
principes stood in the second battle line, behind
hastati in the first line, and in front of the
triarii in the third. If the
hastati failed to break the enemy during their engagement, they would fall back and let the heavier
principes take over. If the
principes could not break through, they would retire behind the heavy
triarii spearmen who would then engage the enemy in turn. The
equites, cavalrymen, were used as flankers and to pursue routing enemies. The
rorarii and
accensi in the final battle line were some of the least dependable troops, and were used in a support role, providing mass and reinforcing wavering areas of the line. Their equipment and role was very similar to the previous system, except they now carried swords, or
gladii, instead of spears. Each princeps also carried two
pila, heavy javelins that bent on impact to prevent them being removed from the victim or thrown back. The
principes had been increased in number to 1,200 per legion, and formed 10 maniples of 120 men each. The
rorarii and
accensi had been disbanded.
Leves had been replaced with
velites, who had a similar role, with forty of them being attached to each maniple in the legion. This order of battle was almost always followed, the
Battle of the Great Plains and the
Battle of Zama being among the few notable exceptions. At the Great Plains,
Scipio, the Roman general, formed his men up in the usual manner, but once the
hastati had begun to engage the enemy, he used his
principes and
triarii as a flanking force, routing the opposing Carthaginians.
Late republic With the
putative reforms of Gaius Marius in 107 BC, intended to combat a shortage of manpower from wars against the
Numidian king
Jugurtha in
North Africa and Germanic tribes to the north, the different classes of units were disbanded entirely with legionaries uniformly armed with
gladius and two
pilum.
Auxiliaries, local irregular troops, would fulfill other roles, serving as
archers,
skirmishers and
cavalry. ==See also==