Poseidon rules the sea, one of the three sons of Cronus and Rhea who divide the cosmos by lot after overthrowing their father; Zeus takes the sky, Hades the underworld, and Poseidon the waters, with the earth and Olympus held in common. He is Earth-Shaker as well as sea lord, credited with the tremors that split open the ground, and his moods pass as quickly as weather over open water — calm one moment, wrecking fleets the next, as Odysseus learns across ten years of wandering after blinding Poseidon’s son, the Cyclops Polyphemus.
He carries the trident, strikes rock to bring forth springs and, in some tellings, the first horse, and rides the waves in a chariot drawn by bronze-hooved steeds beside his consort Amphitrite, a Nereid. Horses stay sacred to him throughout Greece, raced and sacrificed in his honor at the Isthmian Games of Corinth. He contests Athens with Athena and loses, and his temper toward those who cross him — Laomedon of Troy, Odysseus, the Phaeacians — runs through the epics as a reminder that the sea forgives no one twice.
διχθά τοι Ἐννοσίγαιε θεοὶ τιμὴν ἐδάσαντο ἵππων τε δμητῆρ’ ἔμεναι σωτῆρά τε νηῶν
“A two-fold office the gods allotted you, O Shaker of the Earth, to be a tamer of horses and a saviour of ships!” — Homeric Hymn 22, to Poseidon
