The Chronicles of Old Mars:
Martian history is a mess. Although the spoken language is unimaginably ancient, the writing system has changed several times over the millennia. Many of these old systems are untranslatable, rendering entire epochs of the world's history unknown and, most likely, unknowable. Further, the current rulers of Old Mars, the god-kings, have as a group gone out of their way to conceal and muddy the past prior to their ascension. Everyone knows that a conflict known as the Dragon War took place, for example, but few know how long ago or what changed as result.