This article intends to deliver, in a concise and understandable way, a critical summary of the main theories, methodologies and problems that can be implemented and confronted in the contemporary study of republican Roman diplomacy. We will analyze three aspects: first, from realistic political science, the role of republican Roman diplomacy in the coercive and hierarchical establishment of Roman state power; secondly, from a constructivist and sociological interpretation, the role of republican diplomacy as an expressive and revitalizing agent of senatorial and Mediterranean symbolic and socio-political ties; and, thirdly, the role of senatorial commissions in the maturation and complexity of diplomatic work.