POSEIDON, in Greek mythology, god of the sea and of water generally, son of Cronus and Rhea, and brother of Zeus and Pluto (perhaps "lord of see Carnoy in Musee Beige, xxviii. p. 175 or connected with drink, a river). When the three brothers deposed their father, Cronus, the kingdom of the sea fell by lot to Poseidon. His home was in a golden palace in the depths of the sea near Aegae in Achaea. In his hand he bore a trident, wherewith he lashed the sea into fury, split the rocks, and caused horses and fountains to spring from them. But, while he caused storms and shipwrecks, he could also send favouring winds; hence he was known as "the preserver " Another of his titles was Gaieochos, "holder (i.e., encircler?) of earth." He was the god of navigation and his temples stood especially on headlands and isthmuses. Every oc cupation connected with the sea was under his protection, and seafaring people, especially the Ionians, regarded themselves as his descendants. As god of the sea he disputed with other deities for the possession of the land. Earthquakes were thought to be produced by Poseidon shaking the earth—hence his epithet of enosichthon, "earth-shaker"—and hence he was worshipped even in inland places which had suffered from earthquakes. Several striking seismic and other phenomena in historical times were at tributed to him. Poseidon was also the god of springs, which he produced by striking the rock with his trident, as he did on the acropolis of Athens when disputing with Athena for the sovereignty of Athens (Herodotus viii. 55; Apollodorus iii. 14). As such he was called Nympliagetes, the leader of the nymphs of springs and fountains, a god of fresh water, probably his original character, and in this connection was cktyraytos, a god of vegetation, fre quently associated with Demeter. At Athens, he is closely as sociated with Erechtheus (q.v.), with whom many identify him. As he gave, so he could withhold, springs of water; thus the waterless neighbourhood of Argos was supposed to be the result of his anger. Black bulls were sacrificed to him and often thrown alive into rivers; in Ionia and Thessaly bull-fights took place in his honour; at a festival of his at Ephesus the cupbearers were called "bulls," and the god himself was surnamed "Bull Posei don." The horse was especially associated with his worship Sev eral legends represent him as creating the first horse; horses were occasionally sacrificed to him; and he is called Hippios ("lord of steeds") , In the deme of Colonus he was worshipped with Athena, the reputed inventor of the bridle Various explanations of the title l'Jr.irtos have been given : (I) that the horse represented the
corn-spirit; (2) the resemblance of the crested waves to horses; (3) the impression of horses' hoofs near the god's sacred springs, and the shaking of the earth by them when galloping (see Farnell, Cults of the Greek States, iv. 2o). In the Trojan War he takes the side of the Greeks, because he had been cheated of his re ward by Laomedon, king of Troy, for whom he had built the walls of the city. The blinding of his son Polyphemus by Odys seus brings upon the hero the wrath of Poseidon. He is famous for his numerous amours ; his offspring were mostly wild and cruel, like the sea—the Laestrygones, Polyphemus, Antaeus, Procrustes, and the like. He was worshipped as a national god by the Ionians, who took his worship over with them from Peloponnesus to Asia Minor. His chief sanctuary was at Mycale, where the Panionia, the national festival of the Ionians, was held Other seats of his worship were in Thessaly, Boeotia (see Farnell, p. 29 ff.) and Peloponnesus. At Taenarum in Laconia he had a famous cave like temple with an asylum, and on the island of Tenos he was worshipped as the physician, probably in reference to the health giving properties of the sea air. By far the most famous of his festivals was that celebrated every alternate year on the isthmus of Corinth, at which the "Isthmian games" were held. The horse, the dolphin (the symbol of the calm sea) and the pine-tree, with wreaths of which the Isthmian victors were crowned, were sacred to him. His attributes are the trident and dolphin or tunny fish.
As represented in art, Poseidon resembles Zeus, but possesses less of his majestic calm In modern Greece St. Nicholas has taken the place of Poseidon as patron of sailors. But the Zacyn thians have a special sea god. half man, half fish, who dwells under the sea, rides on dolphins or in a car drawn by dolphins, and wields a trident. By the Romans .Poseidon was identified with Neptune (q.v.).
See Preller-Robert, Griechische Mythologie, i. 566 ff. (1894) ; 0. Gruppe, Griechische Mythologie, vol. ii. (19°6) ; and especially L. R. Farnell, Cults of the Greek States, vol. iv. (1907).