Plato was for Cicero the prince among philosophers. Cicero himself identified with Plato in all his richness and abundance as a writer and thinker, but also as a model for the politically engaged intellectual. This chapter studies first Plato’s presence in Cicero’s letters in the period 54–49 bce, the tempestuous years before the Roman Republic was finally torn apart. Then it turns to consider the three major Platonic dialogues composed at that time: De oratore, De republica, De legibus, in which he articulates grand political and cultural ambitions for the orator and a vision of how a republican polity should and could be conceived and conducted. A brief final section looks at the theoretical writings on oratory and philosophy in 46–44, mostly composed during Caesar’s dictatorship, when Cicero’s voice in the public sphere was almost entirely silenced. His main literary efforts were devoted to the construction of a philosophical encyclopedia, in which the systems of the Hellenistic schools became the main focus. His veneration of Plato and his attraction to Platonic idealism in various aspects remain evident. But the intensity of his earlier engagement with Plato has become a thing of the past.