Among the standards approved by the Fourth Lateran Council the XXI stands out as the most important in the sacramental discipline. As usual it takes the name from its opening words, Omnis utriusque sexus. Through it, not only did the Church sanction a universal law that established the obligation of the believer to
confess all his sins to their priest annually, in order to receive at least at Easter, after the execution of the imposed penance, the sacrament of the Eucharist, but also introduced a broader regulation of the same sacrament which brought up a relevant subject such as the sigillum confessionis and the related penalties which were applicable if violated. For the first time this institution, which has its roots in the divine right, received a general and organic legislative discipline intended to become the subject for reflection on the part of the doctrine, especially in the wake of its reception in the Liber Extra by Gregory IX (X 5. 38. 12).
Given a brief excursus on the emergence in the jus vetus of a first regulation in relation to the duty of the Seal of Confession, we will try to understand the impact of l of the Innocentian legislation on doctrinal reflection and the development of the following regulation on the subject between the Middle Ages and the modern age.


Keywords: Confession; sacramental seal; Fourth Lateran Council.