A son of Thestor of Mycenae or Megara, was the wisest soothsayer among the Greeks at Troy. (Hom. Il. i. 69, &c., xiii. 70.) He foretold the Greeks the duration of the Trojan war, even before they sailed from Aulis, and while they were engaged in the war he explained to them the cause of the anger of Apollo. (Il. ii. 322; Ov. Met. xii. 19, &c.; Hygin. Fab. 97; Paus. i. 43. § 1.) An oracle had declared that Calchas should die if he should meet with a soothsayer superior to himself; and this came to pass at Claros, for Calchas met the famous soothsayer Mopsus in the grove of the Clarian Apollo, and was defeated by him in not being able to state the number of figs on a wild fig-tree, or the number of pigs which a sow was going to give birth to -- things which Mopsus told with perfect accuracy. Hereupon, Calchas is said to have died with grief. (Strab. xiv. p. 642, &c., 668; Tzetz. ad Lycoph. 427, 980.) Another story about his death runs thus : a soothsayer saw Calchas planting some vines in the grove of Apollo near Grynium, and foretold him that he would never drink any of the wine produced by them. When the grapes had grown ripe and wine was made of them, Calchas invited the soothsayer among his other guests. Even at the moment when Calchas held the cup of wine in his hand, the soothsayer repeated his prophecy. This excited Calchas to such a fit of laughter, that he dropped the cup and choked. (Serv. ad Virg. Eclog. vi. 72.) A third tradition, lastly, states that, when Calchas disputed with Mopsus the administration of the oracle at Claros, he promised victory to Amphimachus, king of the Lycians, while Mopsus said that he would not be victorious. The latter prophecy was fulfilled; and Calchas, in his grief at this defeat, put an end to his life. (Conon, Narrat. 6.)