Poseidon was the god of the sea, earthquakes and horses. Although he was officially one of the supreme gods of Mount Olympus, he spent most of his time in his watery domain.
Poseidon was brother to Zeus and Hades. These three gods divided up creation. Zeus was ruler of the sky, Hades had dominion of the Underworld and Poseidon was given all water, both fresh and salt.

Well known for his trident and his violent temper, he created animals including the first horse to impress Demeter.  Poseidon was the second most powerful god after Zeus, and he was widely worshipped by seaman