Neptune symbolizes the intangible and the extraordinary. It is the planet of fantasy and dreams (Bruce-Mitford 113).

Poseidon is the Greek god of the sea. He was the son of Cronus and Rhea, and was one of six siblings who eventually "divided the power of the world." Other divinities attributed to Poseidon involve the god of earthquakes and the god of horses. The symbols associated with Poseidon include: dolphins, tridents, and three-pronged fish spears (Lindermans "Poisedon").

Poseidon was relied upon by sailors for a safe voyage on the sea. Many men drowned horses in sacrifice of his honor. He lived on the ocean floor in a palace made of coral and gems, and drove a chariot pulled by horses. However, Poseidon was a very moody divinity, and his temperament could sometimes result in violence. When he was in a good mood, Poseidon created new lands in the water and a calm sea. In contrast, when he was in a bad mood, Poseidon would strike the ground with a trident and cause unruly springs and earthquakes, ship wrecks, and drownings (Lindermans "Poisedon").

In the days of King Cecrops a dispute had arisen between him and Athene for the possession of Attica. To affirm his rights, Poseidon struck the rock of the Acropolis with his trident and a salt water spring gushed forth. The dispute was pronounced in favour of Athene (Hamlyn 119).

Neptune was the god of the sea among the Romans. He was not a very powerful god, and not too much is really known about him. When he was introduced into the Roman world, he seemed very similar to the already existing Greek god Poseidon. Despite Poseidon's great respect from sailors, Neptune was far less popular among them (Lindermans "Poisedon").

Neptune was held in much higher regard as Neptune Equester, the god and patron of horse-racing and horses (Lindermans "Poisedon").