In the ordinary form of the Mass, the prayers which follow are typically intoned or read from the presider’s chair, if they are read at all. In the traditional Latin Mass, they are intoned or prayed from the altar: the Introit and Collect from the epistle (right-hand) side of the altar, the Kyrie and Gloria from the center. One cannot help but be impressed, then, by the fact that the action of the traditional Latin Mass is glued to the altar in a way that it often isn’t in the reformed Mass. Absolutely nothing in the traditional Latin Mass is done which is not, in some way, visibly ordered toward the offering of the sacrifice on Calvary. This is something that goes much deeper than the mere orientation of the priest: it has to do with the orientation of the liturgical action itself.
In the ordinary form of the Mass, the Introit (technically the Entrance Antiphon) through the Collects are considered the “Introductory Rites,” separate from the readings which follow. In the traditional Latin Mass, however, everything from the Introit through the Creed is considered part of the “Mass of the Catechumens,” an ancient title for the first half of the liturgy, which those who were not fully-initiated Catholics were permitted to attend. In the days of the early Church, after the conclusion of the Mass of the Catechumens, the uninitiated (along with notorious public sinners) were required to leave; the so-called “Mass of the Faithful,” corresponding to the modern “Liturgy of the Eucharist,” was open only to fully-initiated Catholics. The practice of ejecting catechumens and notorious public sinners from Mass prior to the offertory had certainly ceased by the time of Pope Gregory the Great in the sixth century.
After the Prayers at the Foot of the Altar, the priest ascends to the altar, proceeds to the epistle side and reads the Introit (aloud at a low Mass, or quietly at a sung Mass; at the latter, the faithful would have already heard the Introit being chanted during the Prayers at the Foot of the Altar). It is generally understood that a traditional Latin Mass begins with the reading of the Introit, the Prayers at the Foot of the Altar being rather of a character of preparation; for this reason, the priest is to render the sign of the cross as he begins reading. The Introit has a few elements: a snippet of Psalm, then the doxology (Glory be to the Father…), bookended on both sides by an antiphon which is usually, but not always, itself from Scripture. For instance, for the Feast of the Sacred Heart (to celebrated this year on Friday, June 12) has the following Introit:
Cogitatiónes Cordis eius in generatióne et generatiónem: ut éruat a morte ánimas eórum et alat eos in fame. (The thoughts of His Heart are to all generations: to deliver them from death and preserve them in spite of famine.) Ps. Exsultáte, iusti, in Dómino: rectos decet collaudátio. (Psalm 32:1. Exult, you just, in the Lord; praise befitteth the upright.) V. Glória Patri, et Fílio, et Spirítui Sancto. (Glory be to the Father, and to the Son, and to the Holy Spirit.) R. Sicut erat in princípio, et nunc, et semper, et in saecula saeculórum. Amen. (As it was in the beginning, is now, and ever shall be, world without end. Amen.) Cogitatiónes Cordis eius in generatióne et generatiónem: ut éruat a morte ánimas eórum et alat eos in fame. (The thoughts of His Heart… .)
(This particular Introit can be heard chanted here, from the beginning to about the 3:15 mark. It is one of my favorites, and a truly lovely example of chant.)
Taken together, the Introit sets the tone, so to speak, for the Mass: whatever character the Introit has, or whatever key truths it seeks to relate, are bound to be echoed, also, in the other propers of the Mass (in the Collect, the readings, the Secret, and the Postcommunion). The integration of the propers and the Scripture readings of the day is a feature unique to the traditional Latin Mass, which the multi-year lectionary of the reformed Mass does not allow.
In the ordinary form, the Introit survives in an amputated form as the “Entrance Antiphon,” consisting only of the antiphon above, recited once (and perhaps followed by an “Alleluia,” at the appropriate time of year). Even then, it is not always heard: entrance hymns more frequently take their place. The Entrance Antiphon may still be recited after the singing is concluded, and is, I think, required to be recited if no singing takes place, but in my experience, this rarely ever happens. I would be interested in seeing how the reformed Mass’ Entrance Antiphons map onto the traditional Mass’ Introits. I am not aware of any readily-available comparison (though the antiphon of Cogitatiónes does appear on the Feast of the Sacred Heart in the reformed Mass).
After the Introit has been read, the priest returns to the center of the altar and commences the Kyrie. There is no vernacular option (“Lord, have mercy”) here, as in the ordinary form: it is to be recited in Koine Greek. Also of note is that the traditional Latin Mass’ Kyrie is ninefold: Kyrie Eleison is said three times (first by priest, then by server, then by priest again); Christe Eleison is said three times (first by server, then by priest, then by server again); then the threefold Kyrie Eleison is repeated in the same way. The numerological implications here are obvious: three Kyries for the Father, three Christes for the Son, three Kyries for the Holy Spirit; the ninefold invocation calls to mind the nine orders of angels, praising God for eternity. In the reformed Mass, the Kyrie’s sixfold recitation (Kyrie, Kyrie; Christe, Christe; Kyrie, Kyrie) reflects the dialogical character of the Mass, and hence forfeits some Trinitarian significance. The ordinary form allows the option of omitting the Confiteor and instead adopting the Kyrie to that end, using vaguely penitential tropes which harken back to the medieval practice of farcing — that is, larding up the Kyrie with additional titles and invocations, eventually suppressed as an abuse.The New Catholic Encyclopedia gives one example of a farced Kyrie from the ancient Sarum Missal (used in York, England, prior to the English Reformation): Kyrie, rex genitor ingenite, vera essentia, eleison (“Lord, King and Father unbegotten, True Essence of the Godhead, have mercy on us”). Incidentally, the farcing of the Kyrie forced it into the long chant settings eventually used, and from which the major chant settings ultimately derived their names (e.g., the Missa de Angelis, the Missa Orbis Factor, etc.), for which reason the book containing chant settings for the Mass was called the Kyriale. At any rate, the practice of conflating the Kyrie and Confiteor seem bizarre to me: the latter is personal, intimate, and penitential, while the former has a more general and intercessory character, begging mercy for the whole world. Something seems lost by foregoing the Confiteor in this way.
After the Kyrie, the Gloria is said, if the occasion is appropriate (if a sung Mass, the priest typically intones the first four words). The Gloria is said more often in the traditional Latin Mass than in the ordinary form of the Mass, as the latter’s calendar is comparatively desolate of saints. Little else differs: the two forms are identical, though the rubrical exactitude of the traditional Latin Mass demands numerous signs of reverence by both priest and server, who are obliged to bow their heads at adorámus te, grátias ágimus tibi, Iesu Christe, and súscipe deprecatiónem nostram, as well as to sign themselves at the final line; all gestures of reverence that were eliminated according to the reform’s unstated principle that verbal communication is to be preferred over symbolic gestures. After the Gloria (if it is said), the priest turns to the people and says Dominus vobiscum, to which they respond Et cum spiritu tuo. This is the first of seven times the Dominus vobiscum is said in the course of the Mass (recall that the Dominus vobiscum said during the Prayers at the Foot of the Altar are technically extraliturgical, since they precede the Introit), and the first of five times it is said while facing the people. There is numerological significance here, too: the seven recitations are to implore the outpouring of the seven gifts of the Holy Spirit; that five of them are said facing the people calls to mind the five apparitions of Christ after his Resurrection.
After the Gloria (or Kyrie, if the Gloria is not said), he proceeds at once to the epistle side of the altar and reads the Collects of the day. It is a prayer which is said over the people who are collected together. Collects follow the same general form and structure in both forms of the Mass, along the lines of “O God, who… grant, we pray, that… through our Lord… forever and ever, amen.” Of note, there may be more than one Collect in the traditional Latin Mass, a form which allows the commemoration of lesser feasts during the celebration of greater ones by joint recitation of some of both feasts’ propers (more on commemoration later). A significant rearrangement of the Collects (some might say butchery) was conducted during the liturgical reform, as documented by Lauren Pristas: of the 66 Collects used for Sundays and holy days of obligation in the reformed Missal, only 34 came from the traditional Missal, barely over half, of which 32 were moved to different Sundays (including all of the Collects of Advent) and of which 13 were substantially revised first. Another 24 Collects (a little over a third) were lifted out of long-disused Missals and liturgical codices, most of them heavily edited in the process; and 8 (about an eighth) were entirely new compositions. Count that as a massive red mark against the Second Vatican Council’s directive that “there must be no innovations unless the good of the Church genuinely and certainly requires them“! For a fuller treatment on the differences in the Collects of the two Missals, see Pristas’ Collects of the Roman Missals: A Comparative Study of the Sundays in Proper Seasons before and after the Second Vatican Council.