Poseidon (/p?'sa?d?n p?- po?-/; Greek: ??se?d??) is one of the Twelve Olympians in ancient Greek religion and mythology presiding over the sea storms earthquakes and horses. He was the protector of seafarers and the guardian of many Hellenic cities and colonies. In pre-Olympian Bronze Age Greece Poseidon was venerated as a chief deity at Pylos and Thebes with the cult title "earth shaker"; in the myths of isolated Arcadia he is related to Demeter and Persephone and was venerated as a horse and as a god of the waters. Poseidon maintained both associations among most Greeks: he was regarded as the tamer or father of horses who with a strike of his trident created springs (the terms for horses and springs are related in the Greek language). His Roman equivalent is Neptune.