a notorious informer raider Tiberius (celebre inter accusatores Trionis ingenium, Tac. Ann. 2.28), and one of the friends and favourites of Tiberius. He is first mentioned in A. D. 16, when he was the chief instrument in procuring the condemnation of the praetor L. Scribonius Libo. In A. D. 20 he accused Piso before the consuls, and in consequence of that service was allowed by Tiberius to become a candidate for the higher honours of the state. In A. D. 31 he was consul with P. Memmius Regulus, in which year Sejanus was put to death. Being a friend of Sejanus, Trio was suspected of favouring his cause, and vehement disputes arose in consequence between the two consuls. By pretending great anxiety to bring the accomplices of Sejanus to justice, the fall of Trio was postponed for a short time ; but in A. D. 35, having been accused and thrown into prison, he did not choose to wait till he was formally condemned, and therefore put an end to his own life, after first making his will, in which he attacked in the severest terms Macro and the principal freedmen of Tiberius, as well as the emperor himself. (Tac. Ann. 2.28, 30, 3.10, 19, 5.11, 6.4, 38; D. C. 58.9, 25.)