Herodotos and Thoukydides report on many occasions that kings, polis leaders, and other politicians speak and behave in ways that unintentionally announce or analyze situations incorrectly (misinformation). Elsewhere, they represent as facts knowingly false constructs or “fake news” (disinformation), or they slant data in ways that advance a cause personal or public (propaganda, true or false). Historians attempt to or claim to acquaint audiences with a truer fact situation and to identify subjects’ motives for distortion such as immediate personal advantage, (...) community advantage, or to encourage posterity’s better (if mistaken) opinion. Such historiographical bifocalism enhances the historian’s authority with readers (as he sees through intentional or unintentional misrepresentations) as well as sets straight distorted historical records. This paper surveys two paradigmatic Hellenic historians’ texts, how they build their investigative and analytic authority, and how they encourage confidence in their truth-determining skills. The material collected confirms and assesses the frequency of persons and governments misleading their own citizens and subjects as well as rival persons and powers. Finally, it demonstrates that these two historians were aware of information loss, information control (dissemination and suppression), and information chaos. (shrink)