Neptune is the Roman equivalent of Poseidon. In Roman mythology, Neptune was considered to be very fearsome and hence was not celebrated much. The Romans were even afraid of travelling by sea without providing appropriate offerings to Neptune. He was the brother of the OlympiansJupiter, Juno, Ceres, Vesta and Pluto. It should also be pointed out that Neptune is more belligerent than Poseidon. Neptune is the son of Saturn and Ops. His wife is Salacia. Along with Mars and Apollo, Neptune was one of only three gods to whom it was appropriate to sacrifice a bull. He was celebrated at the festival of Neptunalia.