Ogygian (adj.)

"of great antiquity or age," 1809, from Greek Ōgygos, Ōgygēs, Ōgygios, name of a mythical king of Attica or Boeotia (or both) of whom nothing is known and who even in classical times was thought to have lived very long ago. Also sometimes with reference to a famous flood said to have occurred in his day.