|Confessionals at Santa Maria Maggiore|
The major external difference between the Roman and Dominican rites of Penance is in vesture. Roman priests traditionally heard confessions in cassock and surplice wearing a purple stole. Dominicans heard (and may still hear) confessions wearing the habit (which is white) and the cappa (the black cape), without a stole. The common explanation of the absence of the stole is that the scapular (a white apron-like part of the habit) is considered a stole. I think this story unlikely as there is no medieval evidence for such an idea. The idea probably arose as an explanation of the practice, not vice versa. The lack of church vestments in our rite is likely a vestige of the early- and high-medieval practice of using vestments only during administration of Public Penance on Holy Thursday. "Private" sacramental penance was not administered with much external formality at the time of the foundation of our Order. The black cappa was worn when not in the monastery and inside the monastery most of the year, so it would have been the normal attire for a friar hearing confessions.
The formulas of Dominican Rite Penance also differ in text and form from those of the traditional Roman Rite. As not all readers may be familiar with the older Roman form, I will describe it first. The comparison is not meant to show that either formula is "better." They are simply different. In the modern period, both rites began with the penitent confessing his or her sins and then proceeded to the absolutions.
The Roman "Common Absolution" began with an invocation of God's mercy (Misereatur tui) similar to the priest's prayer in the modern Penitential Rite at Mass. He then raised his right hand and prayed a short two-part absolution prayer. The first part invoked God's pardon, absolution, and remission of sins in the third person; the second part, the formal absolution, is in first person and first absolved the penitent from excommunication, suspension (if in orders), and interdict, and then from sins with a single Sign of the Cross. The priest then added the prayer Passio Domini Nostri, which remains an option in the new Rite of Reconciliation.
In the Dominican form, the priest begins by absolving the penitent from excommunication, suspension (if a cleric), and interdict, explicitly stating that this restored the penitent to the communion of the faithful. Putting this first reflects the ancient discipline that only those in full communion can pray with the faithful or receive ecclesiastical sacraments and rites. It begins the rite as a whole, so that the penitent would be able to participate in the ceremony that follows.
The Dominican priest then recites the Misereatur in a form identical to that used during the Dominican Prayers at the Foot of the Altar. In thirteenth-century practice, this Misereatur prayer probably followed a ritual now absent from the rite, which was probably found in the Roman as well. It was very common for priests to help penitents make confession by using a Formula Confessionis in question and answer form: "Did you take the Lord's name in vain?" "Did you commit adultery" etc. I studied dozens of these formulae when writing the section on Confession in my book Cities of God. Priests might still "quiz" penitents today, especially if the penitent seems to have trouble identifying sins, or wants help making a general confession. What today is relatively uncommon, such quizzing, seems, from my research, to have been very common in the 1200s. After confessing their sins, penitents said a Confiteor (or some other formula of contrition) to which the priest added the Misereatur prayer, which normally followed it at Mass. Of course, when hearing the friars' confessions, a friar priest would have expected the penitent to know the Dominican Confiteor and use it as his "act of contrition."
The priest then pronounces the Absolution. The Dominican form, in comparison to the Roman, because it lacks the absolution from censures, focuses more directly on sins and judgment. This is a remarkable prayer and incorporates not only the typical thirteenth-century (and current pope's) focus on God's mercy, but also an explicitly eschatological dimension. Here is my translation of the Dominican formula:
May Our Lord Jesus Christ, the Son of the Living God, through his most gracious mercy, absolve you; and by his authority, by which I act, I absolve you of all your sins, so that you be absolved both here and before the tribunal of Our Lord, the same Jesus Christ, so that you might have eternal life and live forever. In the name of the Father + and of the Son + and of the Holy + Spirit. Amen.
Here, for comparison, is the parallel prayer in the Roman Ritual:
May Our Lord Jesus Christ absolve you, and by his authority I absolve you from every bond of excommunication, suspension, and interdict, to the extent of my power and your need. Finally I absolve you from your sins in the name of the Father, and of the Son, + and of the Holy Spirit. Amen.
Note also the triple blessing in the Dominican form, something used in the post-medieval Roman rite of Penance only by bishops. As one of the commentors noted the medieval Roman Rite also had a triple Sign of the Cross, until it was reserved to bishops in the Ritual of 1570. So here, as in a good number of other cases, the Dominican Rite preserves medieval elements dropped or modified in the post-Tridentine Roman Rite.
The Dominican, like the Roman, then concludes with the prayer Passio, which in the Dominican form includes the intercession of St. Dominic along with that of the Virgin, mentions intentions as well as actions, and adds a final blessing in the name of the Trinity. Both the Dominican and Roman rituals provide shortened versions for use when penitents are many and a brief absolution for emergencies. I usually drop the absolution from censures, unless they have been incurred, and omit the Misereatur unless the penitent recites the Confiteor as an act of contrition (which has actually happened!).