Ruler of the Sea
Poseidon was ruler of the sea, earthquakes, and horses. He controlled the storms and when the sea was peaceful. He had a big palace under the sea. He is also know for causing the earthquakes, because he carried a trident with him, which could destroy anything he wanted to when he shook it. He was also ruler of the horses because he gave the first horse to man.
Poseidon's parents were Cronus and Rhea. He had two brothers- Zeus and Hades. He had three sisters- Hera, Hestia, and Demeter. He married Amphitrite, and had four children- Triton, Nymphs, Otus, and Ephialtes.
One of the things Poseidon was known for was he gave the first horse to man.
Poseidon could also control earthquakes.
Stormy sea and sea at peace
He could control when the sea was stormy and rough, and when the sea was peaceful.