The Apostolic Penitentiary (Latin: Paenitentiaria Apostolica), formerly called the Supreme Tribunal of the Apostolic Penitentiary, is one of the three tribunals of the Roman Curia. The Apostolic Penitentiary is chiefly a tribunal of mercy, responsible for issues relating to the forgiveness of sins in the Catholic Church.
The Apostolic Penitentiary has jurisdiction only over matters in the internal forum. Its work falls mainly into these categories:
The head of the Apostolic Penitentiary, the Major Penitentiary, is one of the few Vatican officials who retain their positions sede vacante. If the Major Penitentiary is a Cardinal Elector he is one of only three persons in the conclave allowed to communicate with those outside the conclave, so that he can continue to fulfill his duties (the other two being the Cardinal Vicar of Rome and the Vicar General for the Vatican City State). The Major Penitentiary is a Titular Archbishop and is normally a Cardinal. Since 21 September 2013, the Major Penitentiary is Cardinal Mauro Piacenza. The second-highest-ranking official in the Apostolic Penitentiary, the Regent, is (since 26 June 2012) H.E.Msgr. Krzysztof Józef Nykiel.
In the Papal Bull Misericordiae Vultus (Latin: "The Face of Mercy"), Pope Francis decreed that the Church would observe a Special Jubilee Year of Mercy lasting from the Solemnity of the Immaculate Conception of the Blessed Virgin Mary (a Holy Day of Obligation) on Tuesday, December 8, 2015, until the Solemnity of the Feast of Christ the King of the Universe on the last Sunday before Advent, in November 2016. For this, he allowed certain qualified priests to serve as "Missionaries of Mercy" to each Diocese, with the faculties to absolve even sins that are reserved to the Holy See through the Apostolic Penitentiary. Normally, a priest or even a bishop would not be able to do this unless the person was in danger of imminent death. The Pope has the power, as the earthly absolute sovereign of the Catholic Church, to make this special change for the year.
Up until the 18th century, the Apostolic Penitentiary also considered cases of confessor-penitent disputes involving violations against what was termed the "external forum".
For particularly heinous sins (for example, rape or murder), or for serious sins committed by penitents of high political or cultural standing, it was often the practice to impose rather harsh penances. This practice was particularly true in the medieval Church, for sins referred to a bishop for absolution. If a penitent felt that the penance imposed was disproportionate to the sins committed, he could submit the dispute to the Apostolic Penitentiary. The alleged offense was said to be against the "external forum"; that is, related to public acts required of the penitent.
If the tribunal decided in favor of the penitent, they would issue a formal statement confirming that appropriate recompense had already been made, that the penitent's sins were forgiven, and that the matter was closed.
These statements were transcribed by legal clerks, who were paid by fees assessed by the Apostolic Penitentiary for the transcription of their decisions. This practice prompted claims that the tribunal, and by extension the Church, accepted money for the forgiveness of sins.
Normally confessions of sins are handled at the local level by priests and their bishops and are not heard by the tribunal. The work of the Apostolic Penitentiary involves sins, such as defiling the Eucharist, which are reserved to the Holy See. In late 2006, then Major Penitentiary Cardinal Stafford said this offense is occurring with more and more frequency, by ordinary faithful who receive Communion and then spit it out or otherwise desecrate it.  Other sins that are handled by the Penitentiary include a priest breaking the seal of the confessional by revealing the nature of the sin and the person who sought penance, or a priest who has sex with someone and then offered forgiveness for the act. These sins bring automatic excommunication from the Church. Once the excommunication is lifted, then absolution can be granted. A fourth type of case that comes to the tribunal involves a man who has contributed towards facilitating an abortion, such as by paying for it, or directly so by performing one, who then seeks to become a priest or deacon.
Persons who wish to receive an absolution or dispensation reserved to the Holy See write a petition to the Penitentiary. Usually, this petition is written through their initial confessor. The petition must use pseudonyms when explaining the situation to avoid revealing the identity of the persons involved (which would violate the Seal of Confession), and the tribunal itself acts in complete secrecy. The Major Penitentiary considers the matter himself, unless it is particularly important in which case the whole of the tribunal considers the petition. The members of the tribunal only give advice regarding the petition--the Major Penitentiary has the ultimate decision on whether the dispensation or absolution should be granted. If the Major Penitentiary is uncertain as to whether he has authority in a given case, he submits the matter to the Pope. The impediment or act in question must not be public, as it would then be a matter of the external forum and cannot be absolved or dispensed by the Penitentiary.
The Apostolic Penitentiary also specifies actions for which indulgences are granted, either permanently (in the Enchiridion Indulgentiarum), or on special occasions, such as the Year for Priests (19 June 2009 to 19 June 2010), during which a plenary indulgence is granted, on 19 June 2009, on first Thursdays, on 4 August 2009 (150th anniversary of the death of Saint Jean-Marie Vianney), and on 19 June 2010, to all the faithful who attend Mass, pray for priests to Jesus Christ the Eternal High Priest, offer any other good work they do that day, and satisfy the conditions for any plenary indulgence (detachment from all sins, the Sacrament of Penance within the last or next couple of weeks, holy communion (Eucharist in the Catholic Church), and praying for the Pope's intentions). There are also adaptations for those unable to go to church, and daily indulgences available only to priests.