(Θρασυδαῖος).
1. A citizen of Elis, and leader of the democratic party there. When the Spartans under Agis invaded the Elean territory, in B. C. 400, the oligarchs of Elis, led by Xenias, made an attempt to overpower their political adversaries, and killed, among others, a man, whom, from the likeness between the two, they mistook for Thrasydaeus. The democratic party were hereupon much disheartened, but the mistake was soon discovered, and Thrasydaeus, who, at the beginning of the outbreak, was sunk in sleep from the influence of wine, put himself at the head of the people, and completely conquered the oligarchs. Agis, however, when he retired from Elis, left a Lacedaemonian garrison in Epitalium, and the Eleans were so harassed by the ravages it committed, that Thrasydaeus, in the following year (B. C. 399), was compelled to sue to Sparta for peace, and to purchase it by absolute submission. (Xen. Hell. 3.2. §§ 27-30; Paus. 3.8.) We may perhaps identify with the subject of the present article the Thrasylaeus of Elis, who is mentioned as having been persuaded by his friend Lysias, the orator, to supply two talents to the Athenian patriots under Thrasybulus, in aid of their enterprise against the Thirty Tyrants, B. C. 403 (Pseudo-Plut. Vit. X. Orat. Lys.)