In Greek mythology, he is the god of the sea. His name in Roman mythology is Neptune. Here are some representations in painting and sculpture from various centuries:
He has been borrowed and modified for inclusion in the Marvel Universe where he interacts with Namor, the Submariner…
… as well as the DC universe. Of the images I examined, I didn’t like the mean-spirited tone of most of them (Poseidon going rogue, hitting Wonder Woman, bloody noses, bloody mouths, etc.), so I included only one for this post. This is the best I found for my purposes, and it shows an angry Poseidon battling an angry Aquaman.
DC characters are so angry so much of the time. It strikes me as rather one-dimensional. This is definitely not the DC comics of my childhood.
More examples of shameless borrowing continue next week.