DEMARATUS (Doric Aa/idpaTOS, Ionic A^dpTjros) , king of Sparta of the Eurypontid line, successor of his father Ariston. He is known chiefly for his opposition to his colleague Cleomenes I. (q.v.) in his attempts to make Isagoras tyrant in Athens and afterwards to punish Aegina for medizing. He did his utmost to bring Cleomenes into disfavour at home. Thereupon Cleomenes urged Leotychides, a relative and personal enemy of Demaratus, to claim the throne on the ground that the latter was not really the son of Ariston but of Agetus, his mother's first husband. The Delphic oracle, under the influence of Cleomenes' bribes, pronounced in favour of Leotychides, who became king (491 B.C.). Soon afterwards Demaratus fled to Darius, who gave him the cities of Pergamum, Teuthrania and Halisarna, where his descendants were still ruling at the beginning of the 4th century (Xen. Anabasis, ii. i. 3, vii. 8. 17; Hellenics, iii. i. 6); to these Gambreum should perhaps be added (Athenaeus i. 29 f). He accompanied Xerxes on his expedition to Greece, but the stories told of the warning and advice which on several occasions he addressed to the king are scarcely historical.
See Herodotus v. 75, vi. 50-70, vii. ; later writers either reproduce or embellish his narrative (Pausanias iii. 4, 3-5, 7, 7-8; Diodorus xi. 6; Polyaenus ii. 20; Seneca, De beneficiis, \\. 31, 4-12). The story that he took part in the attack on Argos which was repulsed by Telesilla, the poetess, and the Argive women, can hardly be true (Plutarch, Mul. virt. 4; Polyaenus, Strat. viii. 33; G. Busolt, Griechische Geschichte, ii. 2 563, note 4). (M.N.T.)
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)