Principes

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.

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.

[3][4] 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.

[6] 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.

[10] Pitched battles were conducted in a similar fashion; the velites would gather at the front and fling javelins to cover the advance of the hastati, who had also been re-armed with swords.

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.

Once the surviving elephants had been routed, he formed his men into a long line with his triarii and principes in the centre and hastati on the flanks, ready to engage the Carthaginian infantry.