Illustrated Companion to the Latin Dictionary/Triarii

This article incorporates text from a publication now in the public domain: Rich, Anthony (1849). The illustrated companion to the Latin dictionary, and Greek lexicon. p. vi. OCLC 894670115. https://archive.org/details/illustratedcompa00rich. 

TRIA'RII. A body of heavy-armed infantry soldiers, who formed the third division of a Roman legion. They were originally distinguished by the name of Pilani from the heavy javelin (pilum) with which they were equipped; but when that weapon was also distributed to the other two divisions, comprising the Hastati and the Principes, the old name was changed for that of Triarii, either on account of the position they occupied in the order of battle, viz. the third line, which is the reason assigned by Livy, or because their corps consisted of picked men selected from each of the three heavy-armed classes, which is the reason assigned by Niebuhr. Their armour consisted of a bronze helmet, with a high crest, a cuirass, large shield, a short and pointed sword, and the heavy javelin or pilum; but no authentic monument representing these details with sufficient precision is known to exist. (Varro, L. L. v. 89. Liv. viii. 8.) Towards the latter end of the republic, the original distinction between the men styled respectively Hastati, Principes, and Triarii was abandoned, in consequence of the new system adopted of drawing up the army by lines in cohorts.