The stories of the Sime Gen wars vary according to who is telling the stories, Sime or Gen.
From: RenSime, Ch 1. '...Each mourner was graphically reminded that the first effort to stop the Sime~Gen wars had been made by the Householdings, led by Zeor.'
From: Sime~Gen History
Sime version of history: Gens caused the disintegration -- sniping and pillage went on for hundreds of years, destroying nearly all Ancient knowledge and artifacts. Only Simes had passed on, gathered and cherished some fragments of the old culture.
Householding view: Understanding how the simes had to deny the fact that Gens had "rebuilt portions of the world from which they'd scorned most of the simes and established the Territories."
Ancients had just begun to explore space when mutation occurred --- walked on Mars and sent probes beyond that.
See Sime~Gen History for more information on other topics.