Lore

If you are adding Lore (I think you are, can't remember), maybe there could be unique dungeons/temples/altars/etc. that tie into the Lore/unlock more of it? They could include items unique to the structure (like a [magic?] sword in a pedestal in the main room of a temple dedicated to a previous ancient ruler)? You could pick up the item, then bring it back to some sort of research area to reveal Lore about that area/time period.