The theoretical production and the putting in practice of the medieval right in Castile with relation to the crimes against the social reputation (fama) constitutes a fertile territory to know closely the relations between juridical regulation and values of the Castilian medieval society, as well as the role recovered by the public justice in the resolution of the conflicts in the bosom of the urban society. The analysis of this topic is necessary to approach it from two different areas. On one hand, we analyze the laws about fama and infamia, which was promulgated in the Crown of Castile during the Middle Ages. On other one, we analyze the way in which the courts were used to defend the reputation or to provoke the infamia of the defendants, across analysis of the shameful crimes, as the adultery and the sodomy, and the way in wich the courts become an area of the political struggle of the urban elites.