Poseidon was the Lord of the Sea. His brothers were Zeus - the king of all the gods, and Hades - the king of the underworld. 

Poseidon was a good looking fellow. He had deep blue eyes and streaming green hair.  He was restless, always on the move. 

Poseidon was very powerful. He could raise his hand and a new island would appear! The Greeks were terrified of Poseidon. All the Greeks, but especially those who lived in coastal towns, built a temple to honor Poseidon. They  brought special gifts to the temple every day, hoping to keep him happy. Sometimes it worked. Sometimes it didn't. Poseidon was very moody.

Poseidon had many wives. But his main wife was not jealous, so Poseidon did not have the problems at home that Zeus did.