Poseidon (In Greek: Ποσειδῶν, known as Neptune to the Romans) was considered as the god of the sea. Born of Cronos and Rhea, he had Zeus and Pluto (Hades) for brothers. Poseidon also had three sisters: Hestia, Hera, and Demeter. When Zeus overthrew their father, and the three brothers divided the earth among them, Poseidon became the god of the sea and earthquakes.

When Poseidon desired Demeter, she asked Poseidon to create the world's most beautiful animal in an attempt to cool off his advances. As a result, Poseidon created the first horse and also became the God of horses. In some versions of this story, several other types of animals were created before the horse as a result of Poseidon's several unsuccessful attempts. By the time the horse was created, Poseidon's passion for Demeter had waned.

The symbol Poseidon is associated with is the trident, a weapon which can shake the Earth and shatter any object. Poseidon is often depicted sitting next to his wife, Amphitrite, in his sea chariot pulled by sea creatures.