Poseidon was the Greek god of the seas, lakes, and rivers. His parents were the Titans Cronus and Rhea, and his siblings were Zeus, Hades, and Hera.
Attributes: the triton, the horse, and the bull
Poseidon was married to the goddess Amphitrite, the personification of the sea in female form. Though Poseidon was often unfaithful, she usually stood by her man, except when he showed a little too much love for the nymph Scylla. Her jealousy getting the better of her, she threw charmed herbs into Scylla's bathing pool, and she evolved into a hideous monster.
Poseidon had many children courtesy of his many encounters, often with nymphs.
Poseidon was not happy that, although he ruled such a vast domain, he was still under the ultimate rule of his brother, Zeus. He even tried once to overthrow the king of the gods, with no success.