Private penance was first found in the penitential books of the eighth century, but the beginning of the Sacrament of Reconciliation in the form of individual confession as we know it now, i.e. bringing together confession of sins and reconciliation with the Church, can be traced back to 11th century. By the 9th century the practice of deathbed absolution, without performance of a penance, had led priests to pronounce absolution more widely before the performance of the penance, further separating repentance from forgiveness.
By the twelfth century the formula that the priest used after hearing the confession had changed, from “May God have mercy on you and forgive you your sins” to “I absolve you from your sins.”
From “as early as the third century devout Christians were sometimes encouraged to reveal the condition of their soul to a spiritual guide.” This led to a private form of confession that bishops finally put a stop to by the Fourth Lateran Council (1215) that made confession to a priest obligatory within a year of the sinning, and has enshrined the practice of private confession ever since. In the 13th century the Dominican philosopher Thomas Aquinas tried to reunite the personal “matter” (contrition, confession, satisfaction) and ecclesial “form” (absolution). But the Franciscan Duns Scotus gave support to the prevalent opinion at the time that absolution was the only essential element of the sacrament, which readmitted the penitent to the Eucharist.
In the 11th and 12th centuries a new, legalistic theory of penances had crept in, as satisfying the divine justice and paying the penalty for the “temporal punishment due to sin”. This was followed by a new theory of a treasury of merits which was first put forward around 1230. As a means of paying this penalty, the practice grew of granting indulgences for various good works, drawing on “the treasury of the Church’s merits”. These indulgences later began to be sold, leading to Martin Luther’s dramatic protest.
In the mid-16th century, the bishops at the Council of Trent, retained the private approach to the Sacrament of Reconciliation, and decreed that indulgences could not be sold. However, for Catholics after Trent “the confession of mortal sins would be primarily regarded as a matter of divine law supported by the ecclesiastical law to confess these within a year after they had been committed.”
From the mid-19th century, historical and biblical studies began to restore an understanding of the necessity of repentance for forgiveness by God, before readmission to the Christian community through the sacrament. These studies paved the way for the bishops at the Second Vatican Council (1962-1965) to decree in their Constitution on the Sacred Liturgy: “The rite and formulas for the sacrament of penance are to be revised so that they more clearly express both the nature and effect of the sacrament.” In a post-conciliar document, The Constitution on Penance, Pope Paul VI emphasized “the intimate relationship between external act and internal conversion, prayer, and works of charity.”
The penitent may choose to confess in a specially constructed confessional especially in the West . Since the Second Vatican Council, besides the previous practice of kneeling behind a screen, the option of sitting facing the priest has been added in most confessionals. But for those who prefer anonymity, the provision of an opaque screen separating the priest from the penitent is still required.
The priest administering a sacrament, such as Reconciliation, must have permission from the local bishop, or from his religious superior. But in urgent need any ordained priest may grant absolution to a penitent.