Prometheus was champion of mankind, and brother-in-law of Pandora.
He once stole fire from heaven (Mount Olympus) in order to give it to mortals. In revenge Zeus created Pandora and Pandora's Box (at the time a jar). Pandora became the wife of Prometheus' brother, and Pandora's Box was given to her. Out of curiosity she opened the box releasing all the evil into the world (but closed it before hope could escape). In time the jar was hidden by priestesses of Aegypt, and its shape changed into an evil box.