Neptune was the god of freshwater and the sea in Roman religion.

Residence: Sea
Symbols: Trident, horse, dolphin, bull
Parents: Saturn and Ops
Siblings: Ceres, Juno, Jupiter, Pluto, Vesta
Consort: Salacia
Children: Triton
Greek equivalent: Poseidon
Festivals: Neptunalia
Other Names: Neptune Equestris

Sousse neptune.jpg
Neptune in his chariot, mid-3rd c. AD, Sousse Archaeological Museum.

From early on Neptune had been equated with Poseidon, but was primarily a god of springs, lakes and rivers before becoming also a god of the sea.

Mosaic of Neptune. Regional Archeological Museum Antonio Salinas, Palermo.
A Roman mosaic of Neptune and Amphitrite, House of Neptune and Amphitrite, Herculaneum.
Triumph of Neptune, Roman mosaic with the Seasons in each corner and agricultural scenes and flora, 2nd c. AD, Bardo National Museum.
Triumph of Poseidon and Amphitrite, detail of a vast mosaic from Cirta, c. 315–325 AD, Louvre.