This book examines authority in discourse from ancient to modern historians, while also presenting instances of current subversions of the classical rhetorical ethos. Ancient rhetoric set out the rules of authority in discourse, and directly affected the claims of Greek and Roman historians to truth. These working principles were consolidated in modern tradition, but not without modifications. The contemporary world, in its turn, subverts in many new ways the weight of the author’s claim to legitimacy and truth, through the active role of the audiences. How have the ancient claims to authority worked and changed from their own times to our post-modern, digital world? Online uses and outreach displays of the classical past, especially through social media, have altered the balance of the authority traditionally bestowed upon the ancients, demonstrating what the linguistic turn has shown: the role of the reader is as important as that of the writer.