The proposed study tries to inquire how the legal system allows the litigants to reach a private composition that prevents or ends a lawsuit that has already begun. In particular, it will be analyzed the texts of Title XXXVI of Book I of Decrees of Gregory IX dedicated to the transaction agreement, a contract that gives primacy to the negotiating composition of conflicts and seeks a middle ground between the objectivity of law and the individual affirmation. Particularly, the work aims to describe the legal regime of the transactio by examining and analyzing each of the eleven texts that make up the aforementioned title of Decretals, taking into account, in addition, that doctrinal opinions about them are practically nonexistent. All this without forgetting that the agreement between parties that manifests itself through the transactional solution, is a complementary form of management and resolution of conflicts next to the judicial process and in that way, it is integrated as one more element of the system of organization of Justice.


Keywords: Decretals of Gregory IX; transactio; out of court resolution of conflicts.