Article accepté après évaluation par deux experts selon le principe du double anonymat Paradigmatic fi gures and memorable episodes from the Greek and Roman past are one of the key materials which underlie the discussions performed in Plutarch's Quaestiones convivales. In this learned polyphony, largely based on the conversation with ancient authors (hoi palaioi), the "divine Plato" (Per., 8, 2), celebrated as "a philosopher pre-eminent in reputation and in infl uence" (QC, 700B), assumes the role of a "patron saint" of a new Mediterraneanwide Greek culture. In the opening prologues as in the narrative sequences and the intellectual and ritual practices outlined in this work, Plato emerges as one of the main references of Plutarch's sympotic community. Through the analysis of this tutelary fi gure and its cultural signifi cance in the Quaestiones convivales, this paper aims at emphasising the dynamics and strategies which support the making of a shared cultural memory within the Graeco-Roman "Republic of Letters".