Ἔραστος), of Scepsis in Troas, is mentioned along with Coriscus, a native of the same place, among the disciples of Plato (D. L. 3.46); and the sixth among the letters attributed to Plato is addressed to those two Scepsians. Strabo (xiii. p.608) classes both men among the Socratic philosophers. (Ast, Platon's Leben u. Schrift. p. 519; C. F. Hermann, Gesch. u. System d. Plat. Philos. i. pp. 425, 592, &c.)
[L.S]A Dictionary of Greek and Roman biography and mythology
Smith, William
A Dictionary of Greek and Roman biography and mythology. William Smith, LLD, ed. 1890