This study examines how Tacitus' representation of speech determines the roles of speakers within the political sphere, and explores the possibility of politically effective speech in the principate. It argues against the traditional scholarly view that Tacitus refuses to offer a positive view of senatorial power in the principate: while senators did experience limitations and changes to what they could achieve in public life, they could aim to create a dimension of political power and efficacy through speeches intended to create and sustain relations which would in turn determine the roles played by both senators or an emperor. Ellen O'Gorman traces Tacitus' own charting of these modes of speech, from flattery and aggression to advice, praise, and censure, and explores how different modes of speech in his histories should be evaluated: not according to how they conform to pre-existing political stances, but as they engender different political worlds in the present and future. The volume goes beyond literary analysis of the texts to create a new framework for studying this essential period in ancient Roman history, much in the same way that Tacitus himself recasts the political authority and presence of senatorial speakers as narrative and historical analysis.