This chapter argues that Cicero’s discussion of decorum in De Officiis (1.93-151) represented a striking innovation—both within Cicero’s Roman milieu and in the Greek tradition of his source, Panaetius—for its importation of an aesthetic term, to prepon, into the sphere of ethics. Panaetius’ adoption of this term for philosophical purposes was clever, and one of several innovations that foreshadowed important trends in later philosophy. For Cicero, writing during dramatic social and political upheaval, Panaetius’ innovation represented an opportunity that suited the times. Caesar’s accession had brought profound changes, encouraging a shift from the traditional activities of public self-display to a focus on private self-care and a self-display predicated on written works; as Cicero himself puts it at Off. 2.3, if Caesar had not abolished republican governance, he would still be delivering speeches, not writing philosophy. Moral behavior at Rome had long been governed by exempla, public acts by (usually) public men. By borrowing Panaetius’ suggestion that moral goodness could also be understood in private (and expressly literary/rhetorical terms), Cicero laid the groundwork for a remarkably durable idea in Roman culture, and one with particular resonance in the Augustan period, as Horace’s Ars Poetica shows.