“
Between the sixth and ninth centuries, the practice of public or ecclesial penance began to be replaced by a system of private penance that Celtic monks introduced throughout western Europe. Reconciliation back into the ranks of 'the faithful' had previously been granted only after completion of a public penance lasting many years. By contrast, in the system of private penance, after a penitent's confession (whereby the priest made a judgment and assigned an appropriate penance for the sins committed), reconciliation or absolution was given on the subsequent Holy Thursday or, by the year 1000, immediately. Harsh but shorter private penances, as listed in the penitential books (for example, a considerable repetition of prayers, interspersed with genuflections and long periods of kneeling with hands outstretched in imitation of Jesus on the cross), were now offered as substitutes for the earlier public penances that had taken years to complete. The commutation of penances lasting decades into penances of shorter duration ultimately generated a concern about dying without having fully 'satisfied for' the 'temporal punishment due to sin' in this life, and thereby the fear of being consigned to 'purgatory.' As a result, the offering of Masses for the dead, for a stipend, increased and the granting of indulgences expanded.
Indulgences came from the practice of commuting penances, wherein certain prayers or pious practices were substituted for a longer period of penance in one's lifetime. For example, Pope John the Twenty-Second (1316-34) granted ten thousand days of indulgence to those who recited the prayer Hail Holy Face (Salve sancta facies) while looking at the image of Christ's face on the 'relic' cloth in St. Peter's Basilica. Technically, that pious practice, which also presupposed a pilgrimage to Rome, substituted for twenty-eight years of penance. ... The fifteenth century especially gave rise to the practice of applying such indulgences, or remissions of temporal penances, to souls in purgatory, even though there is no measurement of time beyond death. Pope Sixtus IV (1471-84), who expanded the practice of indulgences, explained that a 'plenary remission' simply offered the suffrage or intercession of the official prayers of the Church for the relaxation of the 'punishments' of the soul in purgatory: 'We, to whom the fullness of power has been given from on high, from the treasury of the universal Church, which consists of the merits of Christ and his saints committed to us, offer help and intercession to the souls in purgatory.' Unfortunately, in the popular mind, and in the exaggerations of some who preached the indulgences offered for a donation to a cause, such plenary remissions were too often misinterpreted as guarantees that souls would be immediately liberated into heaven.
”
”