What would it take to remove a civilisation from history?
As Second Look details over and over again it takes more than war, you need to constantly write your victors fiction over and over and over until all counter memory is dead. War can never kill the memory by itself. Then even when the civilisation is rediscovered one must build a fiction consistent with your given current fiction so that all is contiguous though ridiculous.
We’ll be talking more about that when I crank up the forensic story telling machine again.