While Inca Garcilaso de la Vega (1539-1616) has been widely recognized for his literary contributions, his significance in the realm of historiography has not been unanimously recognized, in part because of the literary quality of his writings. In order to show Garcilaso’s relevance to both literature and early modern history, this study investigates the connection between rhetoric and historiography in La Florida del Inca (1605) and the two parts of Comentarios reales (1609, 1617). Chapter 1 (introduction) proposes a focus on rhetorical amplification (the expansion of a theme, usually in epideictic discourses) as a way to encompass Garcilaso’s argumentative and narrative facets. Chapter 2 provides background information about both Garcilaso’s library and the historiographical tradition. The chapters that follow explore the use of rhetorical amplification in the development of Garcilaso’s themes, method of composition, and story lines. Chapter 3 shows how Garcilaso utilizes his prologues to emphasize encomiastic subjects (namely, heroism, antiquity and honor), while Chapter 4 describes how his method of composition entailed a combination of visual descriptions (evidentia) and the practice of textual annotation. Chapter 5 studies how amplification in La Florida’s narration centers on two types of exemplarity: multiple moral examples based on short episodes, and the development of one cohesive political example involving the death of Hernando de Soto. The two final chapters analyze amplification in the layout of the two parts of Comentarios. Focused on the concept of”mundo”, chapter 6 discusses Garcilaso’s emphasis on universal history and geography to advocate the importance of Peru’s history. Finally, using memory as the unifying topic, chapter 7 explains the interaction between autobiographical passages and collective values. Although La Florida was a monographic project that relied chiefly on examples, and Comentarios was a national and hermeneutical one, the mechanics of amplification in both texts points out changes and continuities within Garcilaso’s trajectory and between him and the historiographical tradition. As a whole, the study of amplification in La Florida and Comentarios helps to highlight the rhetorical basis of historiography and the interaction between political contexts and intellectual traditions in the writing of history.