Why was Frankenstein originally titled the modern Prometheus?

One possibility is based on the myth of Prometheus. If you don't already know, he is the guy who stole fire from the gods and gave it to man. As punishment, he was chained to a rock and an eagle would come and eat his liver after which a new one would regenerate and this would repeat every day. Dr. Frankenstein could be a modern Prometheus as he "stole" the gift of life from "god" and gave it to the human race. The problem is, like fire, this is not something humans know how to use properly so of course, it gets all messed up. What you get then is a mix of fear and pride. Frankenstein's creation ultimately becomes his downfall.