This chapter discusses Plutarch’s On the Oracles at Delphi, and in particular the account of the grammarian Theon as to how prose came to replace verse, not just in the delivery of the Delphic oracle, but in literary discourse as a whole. Theon’s account of the history of Greek literate culture is an important document of how learned Greeks in the Roman empire imagined how their world had changed, along with the literature in which it was represented. The first part of the chapter considers another Plutarchan account of cultural and intellectual change, namely the opening of On the Obsolescence of Oracles, which tells the foundation story of Delphi. Both texts lay weight upon the fact of change itself, rather than on any detailed plotting of that change, let alone a chronology for it; so too, both illustrate a tendency to see recurrent patterns of change, by which the outlines of Greek literary history are found already adumbrated in classical literature itself. Among the classical texts which are central to this appropriation of past models are the programmatic chapters of Thucydides and Aristotle’s account of the development of poetic language.