Prometheus was a cousin of Zeus, according to one tradition he created the first men and always defended them from the anger of gods. Once he stole for mankind the sacred Olympian fire. To punish the mankind Zeus send them Pandora. To punish Prometheus, Zeus ordered him to be chained to a rock in the Caucasus and sent an eagle to consume his liver, which continually renew itself. Zeus swore that Prometheus would never be released. Heracles, however, traveling though Caucasus, shot the eagle and released Prometheus. Zeus did not protest against his son’s deed. Prometheus possessed the power of prophecy and in his turn helped Heracles in his next labour.
See: Peter Paul Rubens Chained Prometheus.