In the first decades of the sixteenth century, humanists such as Erasmus and the Reformers such as Luther and Calvin subjected to a fierce critique the doctrine and practices of sacramental confession. The sacrament of penance and the hearing of confessions were scheduled for debate in each of the three periods of the council: during the first period in the context of the discussions on justiification and indulgences and in the draft canons on purgatory that were not promulgated; in the second period where the traditional teaching and related practices were affirmed in the doctrinal decree on the most holy sacraments of penance and extreme unction approved at that time; and in the third period where the rushed closure of the council prevented a deeper investigation, resting with a merely jurisdictional treatment of the topic.

The printed difusion of the conciliar decrees had a dogmatic character that assured the circulation of the teaching of the Roman Church, approved by the council and promulated by the pontiff, on the basis of which were updated the penitential summas and manuals of the confessors inherited and revised in the last centuries of the Middle Ages and now revised again.

In the pastoral practice after Trent, the effort to establish a control over the observance of the ecclesiastical precept of an annual confession with its registration in an appropriate book failed. Instead, a new ecclesiastical furnishing, the confessional box, appeared that assured at thesame time the making public and the secrecy of the administration of the sacrament.