Unreliable sources and their impact on how we view history

This might be a dumb thing to think about but I was thinking about primary sources in relation to secondary+ sources, and I thought about just how much of our history has been influenced from people who had a biased or a personal stake in the matter (i.e. Plutarch, Gibbon, etc.). <br><br>Another thought I had in relation to that was how people used to view history as the truth and nothing but the truth. Of course now we know that we should take all historical sources with a grain of salt, but I’m interested in how history has been altered over the years by subjective primary sources.