While making clear that the doctrinal integrity of the liturgy is to be maintained, the Council purposely and enthusiastically initiated legitimate modifications to the Tridentine liturgy that would enhance and restore the proper participation of the laity. The liturgical reform was, therefore, principally enacted on behalf of the faithful. Following the directives of the Council, the first typical edition of the Roman Missal was published in 1970, followed by second and third editions in 1975 and 2002. What then do we find in the postconciliar implementation of Sacrosanctum Concilium?
First and most importantly, the active participation of the faithful was heightened in a myriad of ways: in their vocal responses in the Penitential Rite, in the restoration of the Prayer of the Faithful, in the restoration of the offertory procession in which the faithful bring forward the bread and wine, in their response to the priest’s invitation to pray that his sacrifice and theirs would be acceptable to God, and in other responses and acclamations. The role of the altar servers became less prominent. At the same time, many of the prescribed rubrics in the Tridentine liturgy were either dropped or simplified, especially in the new Eucharistic canons. By simplifying the rubrics while simultaneously providing for the laity’s active participation, the reformed rite (known popularly as the Novus Ordo) made the theological character and liturgical significance of the Eucharist more accessible, not only for the laity but also for the presiding priest.
These changes embody one of Vatican II’s enduring and most important achievements: the recovery of the Scriptural and patristic doctrine of the priesthood of all the baptized. As the Council states in Lumen Gentium, “Christ the Lord, high priest taken from the midst of humanity (see Heb 5:1-5), made the new People of God a kingdom of priests to his God and Father (Rev 1:6).” In baptism the faithful are “consecrated as a spiritual house and a holy priesthood” charged with offering spiritual sacrifices, presenting “themselves as a sacrifice, living, holy and pleasing to God (see 1 Pet 2:4-10; Rom 12:1)” (LG §10). This vocation can be perfectly fulfilled only by participating in the Eucharistic sacrifice, and therefore the ordained priesthood was instituted by Christ to permit the priestly people to fulfill their baptismal vocation. “Though they differ essentially and not only in degree, the common priesthood of the faithful and the ministerial or hierarchical priesthood are none the less interrelated . . . . The faithful, by virtue of their royal priesthood, share in the offering of the Eucharist” (LG §10). “Both in the offering and in holy Communion in their separate ways . . . all have their own part to play” (LG §11).
The renewed liturgy empowers the baptized to enact more fully their indelible baptismal character. As the Catechism states: “Incorporated into the Church by Baptism, the faithful have received the sacramental character that consecrates them for Christian religious worship. The baptismal seal enables and commits Christians to serve God by a vital participation in the holy liturgy of the Church and to exercise their baptismal priesthood by the witness of their holy live and practical charity” (CCC §1273). The Eucharist is the most perfect enactment of the baptismal priesthood, made possible by the ordained priest who acts “in the person of Christ the Head.” In it the faithful complete the spiritual sacrifice to which their baptism calls and empowers them (see Rom 12:1; Heb 13:15-16). As the Council taught in its Decree on the Ministry and Life of Priests,
The Lord Jesus whom the Father consecrated and sent into the world (John 10:36) gave his whole mystical body a share in the anointing of the Spirit with which he was anointed (see Matt 3:16; Luke 4:18; Acts 4:27; 10:38). In that body all the faithful are made a holy and kingly priesthood, they offer spiritual sacrifices to God through Jesus Christ . . . .
Through the ministry of priests, the spiritual sacrifice of the faithful is completed [Per Presbyterorum autem ministerium sacrificium spirituale fidelium consummatur in unione cum sacrificio Christi], in union with the sacrifice of Christ the only mediator, which in the Eucharist is offered through the priest’s hands in the name of the whole church in an unbloody and sacramental manner until the Lord himself shall come (see 1 Cor 11:26).
Jean-Pierre Torrell comments on this passage as follows:
The indispensability of the priestly ministry is highlighted by the fact that it is only in the Eucharist that the offering of the spiritual sacrifice reaches its fulfillment . . . . With Presbyterorum Ordinis now we can say specifically that, with this spiritual sacrifice being accomplished by the ministers in the name of all the baptized, the ministers have the lofty role of contributing by their ministry to the completion and perfection of the spiritual sacrifices. Without the sacrifice of the Eucharist the spiritual sacrifices themselves would be deprived of their final flowering.
The Council’s promotion of the faithful’s “full, conscious, and active participation” in the liturgy means that “Christ’s faithful, when present at the mystery of faith, should not be there as strangers and silent spectators. On the contrary, through a good understanding of the rites and prayers they should take part in the sacred action, conscious of what they are doing, with devotion and full collaboration . . . . Offering the immaculate victim, not only through the hands of the priest but also together with him, they should learn to offer themselves” (SC §48).
The Language of the People
Second, what facilitated this intelligibly conjoined liturgical action of priest and laity was the use of the vernacular. Without the vernacular, the active, vocal, intelligible participation of the faithful would have been impossible—at least for the vast majority. Here it is evident that the postconciliar implementation went further than what the Council decreed. As we have seen, the Council Fathers desired that the Latin language be preserved, especially in the people’s responses, although they readily acknowledged that the vernacular was frequently advantageous to the people. What they did not anticipate was the enthusiasm with which the vernacular was accepted by clergy and laity alike. Bishops’ conferences around the world voted to expand the use of the vernacular and requested and received permission to do so from Rome. So widespread was the use of the vernacular that the Vatican decreed in its 1970 General Instruction on the Roman Missal, Cenam Paschalem:
Since no Catholic would now deny the legitimacy and efficacy of a liturgical rite celebrated in Latin, the Council could now concede that “the use of the mother tongue can frequently be of great advantage to the people” (Constitution on the Sacred Liturgy, 36), and it gave permission for such use. The enthusiastic welcome given in every country to this permission has in fact led to the situation in which, under the guidance of the bishops and of the Holy See, all liturgical functions in which the people take part may now be celebrated in the vernacular so that the mystery being celebrated may be the better understood (§12).
The vox populi had spoken and had been affirmed by the Church—vernacular it would be. This ecclesial affirmation undercuts one of the most common arguments against the Novus Ordo: that the wholesale adoption of the vernacular, and the reformed liturgy more broadly, is illegitimate because it went beyond what the Council intended. What this fails to note is that Church’s magisterium, in the persons of Paul VI and John Paul II, confirmed these developments, judging them to be authentic liturgical developments that were in accord with the aims of the Council, even if the Council had not explicitly called for them. This is in stark contrast to the popes’ condemnations of certain theological currents and liturgical practices that claimed to be in continuity with “the spirit of Vatican II” but in fact betrayed the Council; for instance, the denial of the unique saving mediation of Christ, or the practice of ad-libbing the Eucharistic Prayer.
However, a very unfortunate development occurred with regard to the English editions of the Missal: the translations produced by the International Commission on English in the Liturgy (ICEL) were not fully in accord with the Latin original. Many biblical references and allusions were obscured, and the collects and other prayers were rendered in a prosaic manner, losing their spiritual and theological beauty. Moreover, the Eucharistic canons were translated loosely in a way that devalued the sacrificial nature of the Mass. These translations reflected much of the dubious theology that had arisen subsequent to Vatican II. What is even more unfortunate is that the American bishops approved such inadequate translations and the Vatican itself confirmed them. What the Council actually decreed was not fully taken into account. Instead of being taught the proper nature of the Mass through the liturgy itself, as Vatican II intended, the faithful were now deprived of its full theological content.
This unfortunate situation was finally rectified after Pope John Paul II published the third typical edition of the Roman Missal in 2002, and a more faithful English translation was approved by the USCCB in 2010. Nonetheless, the years of unsatisfactory liturgical translations had contributed to the dissatisfaction of many of the faithful.
An Enriched Liturgy of the Word
Third, one of the most pastorally advantageous changes in the reformed liturgy, following the directive of Sacrosanctum Concilium (§51), was the expanded lectionary. The new three-year cycle for Sundays and two-year cycle for weekdays were published in English from 1970 to 1972. This revised lectionary offered the faithful a vastly broader range of readings from the entire Bible, providing them with a rich banquet of God’s word. As the Council Fathers recognized, the proclamation and explanation of the Word of God are not incidental but essential to the liturgy, in order that the faithful may fully appropriate all that is given to them in the sacrament. In the liturgy of the word Christ is proclaimed; in the liturgy of the Eucharist the faithful enter into intimate communion with the Christ they have come to know through his word. Thus the Council teaches that “the Church has always venerated the divine Scriptures just as she venerates the Body of the Lord, since, especially in the sacred liturgy, she unceasingly receives and offers to the faithful the bread of life from the table both of God’s Word and of Christ’s Body” (Dei Verbum §21). As the Introduction to the Lectionary explains, “Through the readings and homily Christ’s Paschal Mystery is proclaimed; through the sacrifice of the Mass it becomes present” (§24). The expansion of the lectionary in turn prompted a ferment of biblical study among the faithful, with the formation of numerous parish Bible studies and biblical study aids.
With the new lectionary, priests were afforded more biblical passages on which to base their homilies. Although the Council declared that the homily is an integral part of the Eucharistic celebration in which “the mysteries of the faith and the guiding principles of the Christian life are expounded from the sacred text” (SC §52), unfortunately many homilies continued to be almost entirely moralistic, with little attention given to the mysteries of faith. Celebrants were fond of telling personal and humorous stories, thinking the congregation would find these more entertaining than the exposition of Scripture. In 2013, the USCCB, acknowledging the widespread dissatisfaction with the quality of homilies, issued a new document that stressed the importance of evangelistic, biblical, and doctrinal preaching in the Sunday homily. In 2015, the Congregation for Divine Worship and the Discipline of the Sacraments published its Homiletic Directory in response to the request of bishops gathered for the Synod on the Word of God in 2008, a request that Benedict XVI made his own in his apostolic exhortation Verbum Domini (§60). The Homiletic Directory (especially §9–15) accentuates the responsibility of the homilist to focus on the Scriptures and provides helpful guidance on how to connect them with the Paschal Mystery made present in the liturgy.
Fourth, Sacrosanctum Concilium had confirmed that the Church’s musical tradition is an inestimable treasure and that music forms an integral part of the liturgy. In order to enable the faithful’s active musical participation, “religious singing by the people is to be skillfully fostered” (SC §52). The Council maintained that Gregorian chant continues to hold pride of place, but also acknowledged the need for incorporating vernacular singing and the musical traditions of various cultures. The implementation of these mandates was decidedly mixed. Instead of teaching Gregorian chant to the faithful, many parishes abandoned it. In most parishes, the Kyrie, Gloria, Sanctus, and Agnus Dei were now recited or sung solely in the vernacular. The loss of the Church’s musical tradition tended to undermine the heavenly solemnity and gravitas of the Mass—something that the Council wanted to preserve when it affirmed the importance of Gregorian chant, which had germinated and blossomed from within the liturgy itself. It must also be remembered that the Spirit’s first inspiration in inaugurating the liturgical movement was in the monastic renewal and promotion of Gregorian chant, and Vatican II wished to maintain that Spirit-inspired stimulus.
The use of the vernacular did give rise to the composition of vernacular hymns and new sung Masses. Some of these were of high biblical and theological quality and skillfully composed, but others were banal and sentimental, with moralistic lyrics, often focused on celebrating the congregating community rather than worshiping Christ. Many were devoid of any mention of the mysteries of the faith, the exaltation of the Holy Trinity, Jesus as the Son of God incarnate, his saving death and glorious resurrection, the new life in the Holy Spirit, or the marvel of the Eucharist. The lyrics of such hymns possessed little biblical or theological correlation to the liturgy itself and were not conducive to entering into the liturgical celebration. Likewise, some of the melodies possessed a liturgical quality, a sacred eminence that would not be found in contemporary secular music. Others, however, sounded like Broadway rejects—a poor combination of “spiritual” words with the tune of contemporary musicals.
With the introduction of vernacular hymns, the use of musical instruments in the liturgy became an issue. In many parishes the guitar became the instrument of choice, often accompanied by other appropriate instruments such as the piano, cello, violin, and flute, all of which can lend beauty to the liturgy and aided the faithful’s participation. Although some had good reason to complain about “guitar Masses,” their distress was sometimes overwrought, fueled by an elitist mentality.
Facing Together—Facing Christ
One other liturgical development that took place after Vatican II deserves discussion in its own right: the placement of the altar with the priest facing the people. Although this change was not anticipated by the Council, once it occurred it was fully embraced by the magisterium. Although either orientation is permitted, we hold that the celebration of the liturgy with the priest facing the faithful is pastorally and theologically more congruent with the reality of the liturgy as “an action of Christ the Priest and of his Body, which is the Church . . . a sacred action surpassing all others” (SC §7). Unfortunately, as will be discussed below, many priests took this innovation as an opportunity to wreak havoc in the sanctuary. Here we enumerate some of the pastoral and theological advantages of the priest and people facing one another.
Sacrosanctum Concilium did not address either the position of the altar in the sanctuary nor whether the priest should face the congregation. Nonetheless, once free-standing altars were introduced, it seemed logical that the priest should face the people for the very reason that the Council promoted the liturgical reform—the full participation of the faithful in the liturgy. Thus the 1970 General Instruction of the Roman Missal (GIRM) prescribed that a church “should have a fixed and dedicated altar, freestanding, away from any wall, so that the priest can walk around it and can celebrate facing the people. It should be in a position such that the entire congregation will naturally focus their attention on it” (262). Likewise the revised 2002 GIRM states: “The altar should be built separate from the wall, in such a way that it is possible to walk around it easily and that Mass can be celebrated at it facing the people, which is desirable wherever possible » (229). Unlike altars prior to Vatican II, which were attached to a wall, the altar now is to be “freestanding” in order for the priest to face the people during the Mass. It is to be positioned such that it can be the focus of both the priest’s and the people’s singular attention. On that altar, in communion with Christ the great high priest, the priest and people together celebrate and offer the one saving sacrifice of the Mass.
That the priest and the faithful face one another during the Eucharistic canon gives full meaning to what Jesus himself declared and enacted at the Last Supper. The priest, in persona Christi, takes the bread and declares to “all of” the faithful that they should “take” and “eat of it, for this is my body, which will be given up for you.” Likewise, the priest takes the chalice and again declares that the faithful should “take” and “drink from it, for this is the chalice of my blood, the blood of the new and eternal covenant, which will be poured out for you and for many for the forgiveness of sins.” All of the faithful present are invited to behold the bread and wine, and are to take, eat, and drink, for in so doing they are incorporated into Jesus’ one saving sacrifice offered to his Father. In eating Jesus’ Spirit-filled, risen-given-up-body and drinking his Spirit-filled, risen-poured-out-blood, they become one with their risen Lord and Savior, and so reap the benefits of new and eternal covenant—everlasting union with the Father in communion with the Holy Spirit. By the priest facing the people, the faithful themselves are drawn into the very mystery they are celebrating together with him. In the elevation of the consecrated bread and wine, Jesus’ own words are fulfilled: “When I am lifted up from the earth, I will draw all men to myself” (John 12:32). Although the priest and people are not facing ad orientem, they are, as at the Last Supper, facing Jesus, and in communion with Jesus, they are offering the perfect sacrifice of praise to their heavenly Father.
The Eucharistic liturgy is, moreover, the renewal and enactment of the everlasting spousal covenant between Christ and the Church. As John Paul II noted,
Christ is the Bridegroom because “he has given himself”: his body has been “given,” his blood has been “poured out” (cf. Luke 22:19-20). In this way “he loved them to the end” (John 13:1). The “sincere gift” contained in the sacrifice of the cross gives definitive prominence to the spousal meaning of God’s love. . . . The Eucharist is Sacrament of our Redemption. It is the Sacrament of the Bridegroom and of the Bride.
In the liturgy, the priest most fully carries out his task of acting in persona Christi: he is the visible sign of Christ the divine Bridegroom, who gives himself entirely to the Church his bride. A bridegroom faces his bride.
Unfortunately, some presiders over the Eucharistic liturgy introduced a grave distortion. Thinking of themselves as being renewal-minded, they assumed the role of an entertainer. Their desire was to make the congregation feel welcome and joyful in order to be fully engaged in the worship experience. However, such priests took liberties that were liturgically inappropriate and even doctrinally erroneous. The entertaining celebrant became the focus of the Eucharistic assembly, leading to a new form of clericalism. Instead of speaking and acting in persona Christi, the priest was in effect speaking and acting in his own person. Some celebrants even improvised their own Eucharistic canons. The result was that instead of the liturgy being renewed and the faithful more actively engaged, it became muddled and banal.
Now, it must be said that many, perhaps most, pastors did their best to implement the Council’s liturgical renewal properly. Nonetheless, it was the misconceived liturgical aberrations that came to symbolize and stigmatize the reform’s implementation. Such deviations were primarily found from the late 1960s to the mid-1980s. By the 1990s most of them became passé, although grave problems remain in some parishes and dioceses. Nonetheless, the postconciliar liturgical deviancies became a catalyst for provoking discontent among some of the faithful, fostering a desire to return to the pre-Vatican II liturgy.
In sum, the implementation of the Council’s reforms had profoundly positive results as well as some inadequate and sometimes harmful effects. The latter were not for lack of ecclesial guidance. In 1964 the Sacred Congregation of Rites issued an Instruction on the Proper Implementation of the Constitution on the Sacred Liturgy. It stressed that only competent ecclesial authority could regulate and implement the liturgical reform. But as witnessed in the above narrative, this document seemed to have had little effect, for deviations continued and even increased. The ultimate cause for why the implementation was not as successful as it could have been, and why so much confusion ensued, is found in the bishops and pastors who were primarily responsible for ensuring its success. The Vatican and bishops either responded to liturgical transgressions after the fact, or in some cases seem to have completely lost control of what was happening on the ground. Few positive measures were taken to correct the liturgical abuses and few disciplinary actions were taken against those who perpetrated them.
Authentic renewal was furthered during the pontificates of John Paul II and Benedict XVI. John Paul II, while applauding all the good that had been accomplished in the liturgical renewal over the thirty years since Vatican II, could still lament that “not all of the changes have always and everywhere been accompanied by the necessary explanation and catechesis; as a result, in some cases there has been a misunderstanding of the very nature of the liturgy, leading to abuses, polarization, and sometimes even grave scandal.” He told a group of American bishops that there was a need to foster “the contemplative dimension of worship, which includes the sense of awe, reverence and adoration which are fundamental attitudes in our relationship with God.” For this reason, “it is so important that liturgical law be respected. The priest, who is the servant of the liturgy, not its inventor or producer, has a particular responsibility in this regard, lest he empty liturgy of its true meaning or obscure its sacred character.” John Paul further encouraged active participation of the laity “through gesture, word, song and service,” as well as “silence, stillness and listening.” He noted that “conscious participation calls for the entire community to be properly instructed in mysteries of the liturgy, lest the experience of worship degenerate into a form of ritualism.” Moreover, he observed that “the use of the vernacular has certainly opened up the treasures of the liturgy to all who take part, but this does not mean that the Latin language, and especially the chants which are so superbly adapted to the genius of the Roman rite, should be wholly abandoned. If subconscious experience is ignored in worship, an affective and devotional vacuum is created and the liturgy can become not only too verbal but also too cerebral.” For John Paul, the Roman rite strikes “the right balance between a spareness and a richness of emotion: it feeds the heart and the mind, the body and the soul.”
We have now traversed the liturgical reform, beginning with its origins in the nineteenth century, as it progressed to Vatican II. We have critically narrated the history of the Council’s reform and the implementation of the new liturgy. We saw that a great deal was accomplished, especially concerning the full participation of the faithful. The implementation was not without its weaknesses, missteps, irregularities, and even aberrations. Nevertheless, we are convinced that the Holy Spirit was present and active throughout this implementation process, even in the midst of anomalies that were not of the Spirit. From the outset of the liturgical renewal to the present, the Church was following the lead of the Holy Spirit and bearing witness to the Spirit in its teachings and actions. To deny the good fruit that the liturgical movement has brought forth during this process would be to deny the Spirit’s enduring infallible guidance. Rather, as John Paul II stated in 1988, on the 25th anniversary of Sacrosanctum Concilium,
we should give thanks to God for that movement of the Holy Spirit in the Church which the liturgical renewal represents; for the fact that the table of the word of God is now abundantly furnished for all; for the immense effort undertaken throughout the world to provide the Christian people with translations of the Bible, the Missal and other liturgical books; for the increased participation of the faithful by prayer and song, gesture and silence, in the Eucharist and the other sacraments; for the ministries exercised by lay people and the responsibilities that they have assumed in virtue of the common priesthood into which they have been initiated through Baptism and Confirmation; for the radiant vitality of so many Christian communities, a vitality drawn from the wellspring of the Liturgy.
In this light, we must now take up the topic of the return to the Tridentine Mass among some clergy and laity in recent times.
EDITORIAL NOTE: This is the third installment of five on the renewal of the liturgy. You can find a link to the second installment at the bottom of this page.
 The Council entrusted the implementation of its principles and decrees to the pope, who in turn established in 1964 a commission devoted to the details of this task (cf. SC §25): the Council for the Implementation of the Constitution on the Sacred Liturgy, informally known as Consilium. Consilium revised the liturgical books and issued several instructions on various aspects of the liturgy. By 1969, when most of its work was completed, Consilium was integrated into the Congregation for Divine Worship.
 Presbyterorum ordinis §2. The Flannery translation is misleading here; the Gonzalez edition (used on the Vatican website) has “is made perfect” instead of Flannery’s pallid “is completed.”
 A Priestly People: Baptismal priesthood and Priestly Ministry (Mahwah, NJ: Paulist Press, 2013), 179.
 It should be noted that celebrating the liturgy in the vernacular is in no way incompatible with the people learning to sing the responses in Latin (or Greek)—the Kyrie, Gloria, Sanctus, Memorial Acclamation, and Agnus Dei.
 The English translation of the new Roman Missal of 1970 was approved for use in the United States by the National Conference of Catholic Bishops and confirmed by the Congregation of Divine Worship in 1973. The English translation of the second typical edition of the Roman Missal (1975) was approved for use in the United States in 1985.
 See Jeremy Driscoll, “Conceiving the Translator’s Task: The Roman Missal and the Vernacular,” in USCCB Ad Hoc Committee on the Forum on the Principles of Translation (ed.), The Voice of the Church: A Forum on Liturgical Translation (Washington, 2001), 49–95; Uwe Michael Lang, The Voice of the Church at Prayer: Reflections on Liturgy and Language (San Francisco: Ignatius, 2012).
 Within the Sunday readings, 41% of the New Testament and 4% of the Old Testament is now proclaimed over the three-year cycle. If the daily readings are included, the percentages rise to 72% and 14% respectively. Critics have rightly pointed out, however, that the new lectionary contains numerous selectively trimmed passages that exhibit a tendentious pattern of omitting unpopular, morally demanding, or “difficult” biblical passages.
 The pattern of a liturgy of the word to which people respond in faith, followed by a liturgy of sacrifice and sacred banquet, appears throughout salvation history, e.g., in Israel’s covenant at Mount Sinai (Exod 24), in the renewal of the covenant under King Josiah (2 Kings 23), in Jesus’ encounter with two disciples on the road to Emmaus (Luke 24:13–32), and in the earliest liturgies of the Church (Acts 20:7–11).
 In 1967 the Congregation for Sacred Rites issued an Instruction on Music in the Liturgy, Musicam Sacram. It again acknowledged that Gregorian chant has a special place in the Roman rite, while equally noting that vernacular singing is of great benefit to the people. For a later statement on the importance of Gregorian chant, see the Sacred Congregation for Divine Worship’s Letter to the Bishops on the Minimum Repertoire of Plain Chant, Voluntati Obsequens (April 14, 1974).
 Those arguing in favor of ad orientem often claim that it continues the ancient and medieval practice. However, textual and archeological evidence shows that the position of the altar and the direction in which the liturgy was celebrated varied widely in the ancient Church. See Robin M. Jensen, “Recovering Ancient Ecclesiology: The Place of the Altar and the Orientation of Prayer in the Early Latin Church,” Worship 89 (March 2015), 99–124.
 Cardinal Joseph Ratzinger, who preferred celebration ad orientem, nevertheless argued against making it the norm again. Instead, he proposes that the altar crucifix “can serve as the interior ‘east’ of faith . . . . In this way we look together at the One whose death tore the veil of the Temple—the One who stands before the Father for us and encloses us in his arms in order to make us the new and living Temple.” Ratzinger, The Spirit of the Liturgy, trans. John Saward (San Francisco: Ignatius, 2000), 83–84.
 John Paul II, Mulieris Dignitatem §26.
 For a further examination of the biblical and theological aptness of celebration facing the people, see Mary Healy, “The Gift of the Liturgical Reform,” Homiletic and Pastoral Review (Jan. 18, 2020).
 It must also be acknowledged that the revisions of the liturgical books themselves were not without flaws. See, for instance, the critique of Lauren Pristas, Collects of the Roman Missals: A Comparative Study of the Sundays in Proper Seasons before and after the Second Vatican Council (T&T Clark Studies in Fundamental Liturgy; London: T&T Clark, 2013); “Theological Principles that Guided the Redaction of the Roman Missal (1970),” The Thomist 67/1 (2003) 157–95; and “The Orations of the Vatican II Missal: Policies for Revision,” Communio 30/4 (2003) 621–53.
 Instruction on the Proper Implementation of the Constitution on the Sacred Liturgy, Inter Oecumenici (Sept. 26, 1964).
The Congregation issued a second Instruction on the Proper Implementation of the Constitution on the Sacred Liturgy, Tres Abhinc Annos, on May 4, 1967. This instruction, in the light of ever-burgeoning chaos within the liturgy, stressed that no one, not even the priest, is permitted to make changes to the Eucharistic liturgy. Moreover, it emphasized that Ordinaries have the obligation before the Lord to ensure that all liturgical practices are in conformity with ecclesial law.
Shortly thereafter the Congregation issued an Instruction on the Worship of the Eucharistic Mystery, Eucharisticum Mysterium (May 25, 1967). Taking into account all the previous instructions, this Instruction provides a lengthy discussion on how the Eucharist is to be celebrated.
 All of the above quotes are taken from Pope John Paul II’s discourse to a group of American bishops at their Ad Limina visit on October 9, 1998.
 John Paul II, Vicesimus Quintus Annus §12. See Driscoll, “Sacrosanctum Concilium,” 25.