The chapter seeks to identify the triple historicity of Cicero’s relationship to philosophy. The first part presents Cicero the historian, who sought to clarify the history of philosophy and its reception in Roman society, as well as to analyze the resistance of his contemporaries to the practice of philosophy, which was considered incompatible with political action. The second part describes the intellectual revolution, under the designation of “reason,” which some of the Roman elite developed as a remedy to the crisis of the Republic; Cicero appears there as the witness par excellence of this intellectual experience in the service of the city. The third part of the chapter examines Cicero the philosopher himself, actor of this revolution. The analysis of his work allows us to see the multiple facets of this man who was also reader, translator, and disseminator of texts and ideas, and to identify his place in relation to his literary milieu, and in particular to his friend Varro.