Re: Quibble:- Trident...Triton... Neptune
IIRC Poseidon was originally the god of horses,hence his sobriquet of the "Earth-shaker". When the peoples whose god he was became a maritime society, he became the god of the sea. ("Um, Poseidon...there's been a bit of a corporate reorganisation, we want you to take on a new role in marketing.")
The Roman Empire just absorbed foreign gods, identifying them with their own if possible. They did exactly the same thing with Christianity, even pinching the Hebrew God, replacing Jupiter, and demoting all the other gods to angels or saints.
Exactly what Disney does with books today.