I know that the Ancient Greeks and Romans had this general theory that societies don't spend time constantly developing, going up and up and up with some bumps in the road, but rather something like a society has a golden age, and then once that fades, they spend all this time (sometimes centuries) trying to achieve that idea again, but never quite get there.
The only thing I can find would be Hesiod's Ages of Man, but it starts with myth and Cronus creating the gods, so....it's not like it's an actual historic period.
Is there a generalized term for that concept? Hesiodic cultural theory?
The Hellenistic/Roman historian Polybius developed a theory he called anacyclosis: he believed societies cycled through three distinct up and down phases—monarchy, aristocracy, and democracy—each of which degenerated into a corresponding corrupt form—tyranny, oligarchy, and mob rule—before collapsing and giving rise to the next phase. (Mob rule would be followed by monarchy, so the cycle would repeat indefinitely.)