He was a god of many names and attributes. The son of Cronus and Rhea, Poseidon was one of six siblings, and the males eventually divided the powers of the universe. His brother Zeus became ruler of the sky, his brother Hades was given the underworld, and Poseidon received responsibility for the seas, as well as, earthquakes, horses, and with his sister Demeter, fertility.
As with most of the Greek and Roman deities, Poseidon was a personality of contradictions. He was moody and tempermental, creating new lands and calm seas when happy, and causing unruly waters, earthquakes, ship wrecks, and drownings when in a bad mood.
He was a lover of women, taking them gently when possible, but using force when needed. He fathered numerous children, Triton who was half-human and half-fish, Pegasus the flying horse, Eumolpus the giant sinis, Orion, and Proteus who could change himself into anything, just to name a few.