(Θόας), an Aetolian, who was praetor of that nation in B. C. 193, and at a council held at Naupactus, took a prominent part in urging his countrymen to war with Rome, and advised them to send embassies to Philip and Antiochus. These, However, produced no effect for the moment, and the following year (B. C. 192) we find Thoas engaging on his own account in an unsuccessful attempt to reduce the important fortress of Chalcis. But circumstances now caused Antiochus to lend a more favourable ear to his overtures, and having repaired in person to join the king in Asia, he obtained.great influence over his mind, and, by his magniloquent promises, was mainly instrumental in persuading him to pass over in person with his army into Greece. Here also he readily induced the Aetolians, who were assembled in council at Lamia, to conclude an alliance with Antiochus, and place themselves under his command. We do not, however, hear any thing of the services which he rendered to the king during the during the war that followed ; while by the advice which he had given at the comencement, he had prevented Antiochus from availing himself of the important assistance of Hannibal. After the defeat of the Syrian monarch the Romans made the surrender of Thoas one of the conditions of the peace which they granted him : but though this demand was complied with, they were induced to set him at liberty at the intercession of Nicander and Pantaleon. At a subsequent period, however (B. C. 169), having again taken an active part against these last partizans, he fell a victim to the popular indignation, being assailed with stories by the assembly of the people. (Liv. 35.12, 37, 38, 12, 45, 37.45, 38.38; Plb. 21.14, 22.26, 28.4; Diod. xxix. Exc. Legat. p. 621, Exc. Vat. p. 71.)