It’s been observed that Edgar Rice Burroughs’ John Carter was an early inspiration for the modern superhero. I believe he was actually a direct inspiration for the genesis of Superman. But what if we go further back?
The Greek heroes like Hercules and Perseus and Achilles are no-brainers, but what if we go even a little further back?
What about Prometheus? It seems to me that a decent argument can be made that the compassionate and tricky god-like champion of mankind was an early progenitor of the notion of a superhero.
Aside from his most famous feat of stealing fire for mankind (and enduring a great punishment for doing so), Prometheus is most known for his cleverness, craft, and trickiness. He’s often associated with science and sometimes with metalworking. None of these powers are as cool as being the god of thunder or of the sun, but they allowed him to foster the development and well-being of mankind, which is one of the primary functions of a superhero.
Being an overpowered god-thing doesn’t hurt, either.
Even if we can’t pick out many modern Promethean superheroes (or at least I can’t, maybe because I’m not much of a comic guy), he serves as a powerful archetype. Throughout the years there have been other mythical and fictional figures who have served similar roles, whether or not they were directly inspired by the Greek titan.