Similarities and Differences on Poseidon and Neptune
Poseidon and Neptune were both the gods of the sea and water. They also were both the brothers of Zeus (Jupiter) and Hades (Pluto/Dis). One way that they were different was that Neptune was originally only the Roman god of the water. He wasn't the god of the ocean until the Romans identified him with the Greeks god, Poseidon. Then, they expanded his kingdom to the whole sea.