Prometheus

In addition to being punished for giving fire to (and favoring) mankind, Prometheus was also imprisoned because he knew a secret that threatened Zeus's reign as Ruler of the Gods. He was told by his mother, Gaea, that a son would be born to Zeus that would overthrow him- and also who the mother was. But no matter how he was tortured, Prometheus knew he was being unjustly punished and he would not reveal the secret.