Regarding the suppressed history, I wonder if you refer to early epochs (like the Lemur and the ten cities of Kadaikos, which got suppressed by Laanx mainly, but chronicles do exist as two in-game books); this epoch is briefly documented in the "History" page.
More details about early events from the founding of the Octarchy during the fifth epoch of "the two temples" can probably be collected across the history of each race, I remember some intrigues being mentioned in the relations between Ylians and Enkidukai.
But without prior knowledge which of the many in-game books may be relevant, it may be time consuming to read through all the books in "Jayose's" developer library; not all book titles are obvious enough to grab attention of the seeker of historical knowledge.