Diplomacy has been developing as a special field of study in ancient history, separate from international relations and institutional or political history. What distinguishes Roman diplomatic practices during the Republic is its gradual secularization, which can be seen in the use of negotiation, in diplomatic personnel, and in protocol. The contributions in this volume look at the characteristics and implications of this new diplomatic practice: its external patterns, the political and institutional construction of the decision-making process, the authority governing the decision making, and the knowledge that underlies the diplomatic decision and guarantees its efficacy.