A recurring pattern in Greek myth has Poseidon contend for the patronage of a city and lose. For Athens he struck the Acropolis and produced salt water (or a horse); Athena gave the olive and was chosen, and one strand of the tradition has Poseidon flood the Attic plain in anger. He disputed Corinth with Helios, Argos with Hera, Aegina with Zeus. The stories are not random: they seem to record real historical friction, the settling of an older, powerful god into a subordinate place as the Olympian order took its classical shape.
He was not left without honour. At Athens he was worshipped on the Acropolis as Poseidon-Erechtheus, fused with a local hero-king, and his trident-mark and salt spring were shown there for centuries. His great Panhellenic sanctuary was the Isthmus of Corinth, where the Isthmian Games were held in his honour, and the temple at Sounion, on the cliff at Attica's tip, greeted every ship approaching Athens.
The Odyssey gives the sharpest portrait of his character: implacable in a grudge, able to raise a storm at will, yet bound like the other gods by the larger decisions of Zeus and fate.