[comrade1234]

I've always liked stories about the post-Roman empire when you still had evidence of a richer and more civilized time that your ancestors lived in but you were stuck in your time. I know it's probably fiction, but I always got that fix from King Arthur stories.

It took a couple of hundred years after that before Charlemagne and law and civilization again.

[recursivecaveat]

I think it was a pretty common pre-modern (not by any means extinct today) academic view that the arc of history was generally towards the decline of civilizations. Like our ancestors were great and amazing and we're just kindof pale imitations of them. It probably doesn't hurt that when the two most important sources of authority in your society are noble title/blood and religion, your ancestors are much closer connected to the source of those.

Modern fantasy picks up this trope, where the most powerful magic and the greatest structures etc are always in the past, only being rediscovered by people in the now.

[Planktonne]

If you haven't yet read The Eagle of the Ninth and its sequels, you might really like them. They're set in Britain that is slowly going post-Roman, and the change in culture is a significant theme.

[dotancohen]

Was that the book that opens with a child running barefoot, and later playing an instrument to entertain guests against his desires? I began reading that book four decades ago and have been unable to find it since.