Poseidon was one of the Twelve Olympians in ancient Greek religion and myth, god of the sea, storms, earthquakes and horses. In pre-Olympian Bronze Age Greece, he was venerated as a chief deity at Pylos and Thebes. He had also the cult title "earth shaker". In the myths of isolated Arcadia he is related with Demeter and Persephone and he was venerated as a horse, however it seems that he was originally a god of the waters.[3] He is often regarded as the tamer or father of horses, and with a strike of his trident, he created springs which are related with the word horse.

His Roman equivalent is Neptune.

Poseidon was protector of seafarers, and of many Hellenic cities and colonies.