Background

Prometheus's first myth appeared in the late 8th century. He was a son of the Titan, Iapetus by Themis or Clymene, one of the Oceanids. He was brother to Menoetius, Atlas, and Epimetheus.

"Prometheus played a trick against Zeus. He placed two sacrificial offerings before the Olympian: a selection of beef hidden inside an ox's stomach, and the bull's bones wrapped completely in "glistening fat". Zeus chose the latter, setting a precedent for future sacrifices; henceforth, humans would keep the meat for themselves and burn the bones wrapped in fat as an offering to the gods. This angered Zeus, who hid fire from humans in retribution. Prometheus in turn stole fire and gave it back to mankind. Prometheus, in eternal punishment, is chained to a rock in the Caucasus, where his liver is eaten out daily by an eagle, only to be regenerated by night, which, by legend, is due to his immortality, eventually the Greek hero Heracles shoots the eagle and frees Prometheus from his chains."

- explained in Hesiod's Theogony.