Perspective can change over time both for individuals and societies so how do historical events in your stories reflect that? Can you show why the perspective changes (for example, more information is now known about an event which makes interpreting it now more meaningful?).
Politics and religion can have radical implications on perspective too so do you need to bring that into your story or to show how your characters are affected by these?
And whose story are you telling? Whose perspective is the most important that the story has to carry?