Keywords: Diplomacy, Political practice, Reason of State, Aragonese Naples.
During the 15th century, diplomacy in Italy underwent an extraordinary formalization process. The aims of diplomatic action were increasingly well defined, and the role of the ambassador was regulated and disciplined. A kind of standard diplomatic representation was reached by a common patrimony of gestures and words within those places predisposed for diplomatic communication. However, this system showed some rifts: cracks in which the seed of those forms that were to give life to the political season of the Reason of State was able to sprout. This essay analyzes precisely these cracks, starting from a privileged vantage point: the Aragonese court of Naples, which was one of the cradles for that new political practice.