(Ἰασίων), also called Iasius, was, according to some, a son of Zeus and Electra, the daughter of Atlas, and a brother of Dardanus (Apollod. 3.12.1; Serv. ad Aen. 1.384; Hes. Th. 970; Ov. Amor. 3.10, 25); but others called him a son of Corythus and Electra, of Zeus and the nymph Hemera, or of Ilithyius, or of Minos and the nymph Pyronia. (Schol. ad Theocrit. 3.30; Serv. ad Aen. 3.167; Eustath. ad Hom p. 1528; Hyg. Fab. 270.) At the wedding of his sister Harmonia, Demeter fell in love with him, and in a thrice-ploughed field (τρίπολος) she became by him the mother of Pluton or Plutus in Crete, in consequence of which Zeus killed him with a flash of lightning. (Hom. Od. 5.125, &c.; Hes. Th. 969, &c.; Apollod. l.c.; Diod. 5.49, 77; Tzetz. ad Lycoph. 29; Conon, Narrat. 21.) According to Servius (Serv. ad Aen. 3.167), Iasion was slain by Dardanus, and according to Hyginus (Hyg. Fab. 250) he was killed by his own horses, whereas others represent him as living to an advanced age as the husband of Demeter. (Ov. Met. 9.421, &c.) In some traditions Eetion is mentioned as the only brother of Dardanus (Schol. ad Apollon. Rhod. 1.916; Tzetz. ad Lycoph. 219), whence some critics have inferred that Iasion and Eetion are only two names for the same person. A further tradition states that Iasion and Dardanus, being driven from their home by a flood, went from Italy, Crete, or Arcadia, to Samothrace, whither he carried the Palladium, and where Zeus himself instructed him in the mysteries of Demeter. (Serv. ad Aen. 3.15, 167, 7.207; Dionys. A. R. 1.61; Diod. 5.48; Strab. vii. p.331; Conon, l.c.; Steph. Byz. s. v. Δάρδανος.) According to Eustathius (Eustath. ad Hom. p. 1528), Iasion, being inspired by Demeter and Cora, travelled about in Sicily and many other countries, and every where taught the people the mysteries of Demeter. (Müller, Orchom. pp. 140, 260, 452; Voelcker, Mythol. des Japet. Geschlechtes, p. 94.)
[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