Roman god of the sea, Neptune was originally a Roman god of fresh waters until he was equated with the Greek Poseidon. He may be derived from the Etruscan god of water, Nethuns.
AS chief of the water deities, HIS symbol of power was the trident, or spear with three points, with which he shattered rocks, called forth or subdued storms, shook the shores, and the like. He created the horse, and was the patron of horse races. His own horses had brazen hoofs and golden manes. They drew his chariot over the sea, which became smooth before him, while the monsters of the deep gambolled about his path.
His festival, the Neptunalia, was held on July 23, the height of the midsummer drought, probably a reference to Neptune’s original role as a god of the fresh waters essential to agriculture. Otherwise, Neptune’s representation in ROMAN art and literature was essentially identical with that of Poseidon.