Neptune with Trident uploaded by Steve via Flickr
Neptune originally was the Roman god of freshwater, including rain and fertility. Later in 399 BCE Neptune become identified with the Greek sea god Poseidon. His wife was Salacia.
The powerful and militaristic Romans eventually made Greece a province of Rome in 146 BCE but they were strongly influenced by the rich depth of Greek myth and culture.
So depictions of Neptune in mosaics, especially around North Africa, were strongly imbued with Greek aesthetics.
Like the Greek Poseidon, Neptune was additionally worshipped by the Romans as Neptunus Equester, the god that overlooks horse-racing.
Also from the Greek tradition, Neptune was the brother of Jupiter and Pluto. The three brothers governed the heavenly, earthly and underworld realms.
Neptune and Triton at Victoria and Albert Museum, London, England – Wikipedia
Neptune had two main temples of worship in ancient Rome. His festival was…