Tria'rius, Vale'rius
1. L.
Valerius Triarius, was quaestor urbanus in B. C. 81 (
Cic. Ver. 1.14), and subsequently praetor.
He was propraetor in Sardinia in B. C. 77, when he repulsed Lepidus who had fled into that island after his unsuccessful attempt to repeal the laws of Sulla. (Ascon.
in Scaur. p. 19, ed. Orelli.) Triarius served under Lucullus as one of his legates in the war against Mithridates, and at first gained considerable distinction by his zeal and activity. [For details, see LUCULLUS, p. 833.] In B. C. 68 Triarius was despatched to the assistance of Fabius, who had been intrusted with the defence of Pontus, while Lucullus invaded Armenia, and who was now attacked by Mithridates with overwhelming numbers. Triarius compelled Mithridates to assume the defensive, and early in the following year he commenced active operations against the Pontic king. Anxious to gain the victory over Mithridates before the arrival of Lucullus. Triarius allowed himself to be attacked at a disadvantage, and was totally defeated with great slaughter. From the expression of Cicero (
de Leg. Man. 9) we might conclude that every man in the army perished; but this does not appear to have been the case. Plutarch says that seven thousand Romans fell, among whom were a hundred and fifty centurions and twenty-four tribunes; and that Lucullus, who arrived a few days afterwards, was obliged to secrete Triarius from the fury of his troops.
This fatal battle, which was one of the severest blows that the Roman arms had sustained for a long time, was fought near Zela, at the same spot where Caesar afterwards gained a victory over Pharnaces. (Appian,
Mith. 88, 89, 112, 120 ; Plut.
Pomp. 35 ; D. C. 35.10-
12; Cic.
de Leg. Man. 9 ; Liv.
Ep. 98 ; Plin. Nat. 6.3.) In Livy (
l.c.) the praenomen of Triarius is erroneously
Caius. 
