1. A son of the Arcadian Lycurgus and Cleophile or Eurynome, and father of Agapenor. (Apollod. i. 8. § 2, iii. 9. § 2, 10. § 8; Hygin. Fab. 173; Hom. Il. ii. 609.) He was one of the Argonauts and partook in the Calydonian hunt, in which he was killed by the boar. (Apollod. i. 9. §§ 16 and 23; comp. Paus. viii. 5. § 2, 45. § 2; Apollon. Rhod. ii. 894; Ov. Met. viii. 400.)
2. A son of Poseidon and Astypalaea or Alta, king of the Leleges in Samos, and husband of Samia, the daughter of the river-god Maeander, by whom he became the father of Perilaus, Enodos, Samos, Alitherses, and Parthenope. (Paus. vii. 4. § 2; Callim. Hymn. in Del. 50.) This hero seems to have been confounded by some mythographers with Ancaeus, the son of Lycurgus; for, according to Hyginus (Fab. 14), Ancaeus, the son of Poseidon, was one of the Argonauts, but not the other; and Apollonius Rhodius (ii. 867, &c.) relates, that after the death of Tiphys, Ancaeus, the son of Poseidon, became the helmsman of the ship Argo, which is just what Apollodorus relates of Ancaeus, the son of Lycurgus. Lycophron (449), moreover, in speaking of the death of the son of Lycurgus by the Calydonian boar, mentions a proverb, which, according to the Scholiast on Apollonius (i. 185), originated with Ancaeus, the son of Poseidon. The story of the proverb runs thus : Ancaeus was fond of agricultural occupations, and planted many vines. A seer said to him that he would not live to taste the wine of his vineyard. When Ancaeus afterwards was on the point of putting a cup of wine, the growth of his own vineyard, to his mouth, he scorned the seer, who, however, answered, polla metaxu kulikos te kai cheileôn akrôn, "There is many a slip between the cup and the lip." At the same instant a tumult arose, and Ancaeus was informed that a wild boar was near. He put down his cup, went out against the animal, and was killed by it. Hence this Greek phrase was used as a proverb, to indicate any unforeseen occurrence by which a man's plans might be thwarted. (See Thirlwall in Philolog. Museum, vol. i. p. 106, &c.)
3. A third Ancaeus occurs in Il. xxiii. 635.