This book analyses Pliny the Elder’s Natural History as a textual unit - its 37 volumes - based on the idea of Romanity founded on Greco-Roman culture and the problem of identities in Antiquity. In the first century, in an increasingly multicultural and multiethnic Empire, the Pax provided by the rise of the Flavian dynasty extended the process of Romanisation, in which Pliny participated as an intellectual in the circle of power. Through Natural History, its rhetoric of writing and reading and theories about identities in the ancient world, we propose to reflect on the concept of romanitas as an idea of Roman identity, supra-ethnic and an ideal model of social behaviour, based on the emulation of Roman customs, Greek art, the city of Rome and the court of Vespasian, the new Augustus. Natural History as Enkyklyos Paideia was the bearer of a thesaurus, which re-proposed the return to traditional Greco-Roman values as a political and pedagogical ’project’ and, at the same time, described aspects of the historical conjuncture of the time of Pliny the Elder, the Julio-Claudian and Flavian Principalities, of crises, Pax and the integration of diverse peoples.