@internetarchive At various points in Chinese history, rulers came in who wanted all knowledge of previous rulers expunged. They went often to very ... extreme, let's call it ... measures to accomplish this erasure.

What saved the knowledge from extinction?

Essentially piracy. Copies of forbidden texts made and circulated in the underground, stored for when, inevitably, said ruler dies and the texts could be resurfaced.

Let me get my pirate's hat. I've got work to do.