Triarii, literally – “the third liners” were legionaries fighting in the third line of the maniple of the Roman Republic. The name “triarii” comes from the word “three” (tres).
In the singular triarius, armed with long for about 3 meters spear (hasta) which made the fighting method similar to classic hoplites.
Besides the spear, they had gladius (a short sword) and scutum (a shield) which were typical to the other legionaries. Triarii had greaves, helmets (cassis), and chainmail. Like in the other maniples triarii had to collect their equipment themselves. According to Polybius’ traduction condition of the defensive armament of hastati, principes and triarii were the same and depended mainly on the wealthiness of the soldier. Protective equipment of the third line was much better than principes and hastati which was caused by higher wages of the veterans.
Triarii were the oldest (from 30 to 46) most experienced and the best soldiers in the legion. They were the reserve line who fought only in the critical moments when the other two lines were defeated. This is how the old roman saying was made: res ad triarios venit which means “Things have come down to the Triarii”, to a dire situation.
Triarii were divided into 10 maniples 60 soldiers each which were divided into 2 centuries 30 men each.