Poseidon was the Greek God of the seas, the horses and the earthquakes.
Family of Poseidon
Parents: Poseidon was a child of the Titans Cronus and Rhea.
Siblings: Poseidon had five siblings. Two brothers (Zeus and Hades) and three sisters (Hestia, Hera and Demeter).
Wife: the sea-goddess Amphitrite. However, according to a tradition, Poseidon was married more than once.
Famous Children: the merman Triton , the Nymphs Rhode and Benthesicyme and the twin giants Otus and Ephialtes.
The Personality of Poseidon and his Way of Life
Poseidon was considered to be the bad-tempered, moody and greedy god among the Olympians. Once insulted, he would revenge himself, like he did in the case of Odysseus, who brutally blinded his son, the Cyclops Polyphemus . Poseidon loved to cross the oceans and seas with his golden chariot surrounded by dolphins.
The Powers of Poseidon
Poseidon was the Greek god responsible for natural and supernatural events, mainly the ones associated to the sea world and was the savior of ships. He possessed a trident which was so powerful that it could shake the earth. Poseidon was able to cause tempests and earthquakes, drown lands, shatter rocks and had the ability to finally bring back peacefulness.
Poseidon possessed two palaces, the one was up in Mount Olympus and the other was located in the depths of the seas and was bejeweled with gold and precious gems. Usually Poseidon preferred to stay with his wife Amphitrite beneath the ocean.
Appearance of Poseidon
Poseidon was imposing and strong with long, blue hair. 
Symbols of Poseidon
The symbol of Poseidon was the trident and his sacred animals were the dolphin and the horse. According to a tradition, he was the one who breathed life into the first horse on earth.
The Roman name of Poseidon is "Neptune"