The present paper aims to provide some directional guidance about the meaning of panhellenism and "common peace" (koine eirene) in the Greek world as these were understood by Arrian of Nicomedia. For this, we will study his main work, Anabasis of Alexander (Anabasis Alexandrou), which will allows us to understand how the author faced the Hellenic idiosyncrasy in a world dominated by the Romans, and also to glimpse not only the historian, but the individual and his reflections on the past and present of the polis.