Pope Pius XII presented an encyclical to the world, Mediator Dei (31 page booklet), 60 years ago today. It was addressed "to the Venerable Brethren, the Patriarchs, Primates, Archbishops, Bishops, and other Ordinaries in peace and communion with the Apostolic See". It concerned the Sacred Liturgy; His Holiness focused primarily on "the Latin liturgy ... not because We esteem less highly the venerable liturgies of the Eastern Church", but because of "a special situation prevailing in the Western Church, of sufficient importance, it would seem, to require this exercise of Our authority." (n. 11)
Yes, even 60 years ago, there was in the Western Church a "special situation" of "sufficient importance" to warrant the exercise of the Pope's universal authority over the whole Church. (Much like there has been a special situation of sufficient importance for the past few decades, which resulted in Pope Benedict XVI acknowledging the right of every priest to celebrate the Mass according to the Missal of 1962, which is the Extraordinary Form of the one Roman Rite.)
Pope Pius XII wrote this encyclical in light of "a remarkably widespread revival of scholarly interest in the sacred liturgy took place towards the end of the last century and has continued through the early years of this one" (no. 4). Some good came out of it, indeed, but the Holy Father recognized that not all was well:
But while We derive no little satisfaction from the wholesome results of the movement just described, duty obliges Us to give serious attention to this "revival" as it is advocated in some quarters, and to take proper steps to preserve it at the outset from excess or outright perversion.The 210 paragraphs of the encyclical talk about the liturgical practices of the Church, most importantly the "august sacrifice of the altar". Of particular note is n. 20, which is a basis (I would surmise) for nn. 34-39 of Mysterium Fidei of Pope Paul VI in 1965, wherein the ways in which the Lord Jesus is present in the liturgy are described. The document defends the ministerial priesthood, the sense of the sacred in the liturgy, the use of Latin, and the sacrificial nature of the Mass. It argues against a sense of "antiquarianism", the false zeal for that which is ancient simply because it is ancient:
Indeed, though we are sorely grieved to note, on the one hand, that there are places where the spirit, understanding or practice of the sacred liturgy is defective, or all but inexistent, We observe with considerable anxiety and some misgiving, that elsewhere certain enthusiasts, over-eager in their search for novelty, are straying beyond the path of sound doctrine and prudence. Not seldom, in fact, they interlard their plans and hopes for a revival of the sacred liturgy with principles which compromise this holiest of causes in theory or practice, and sometimes even taint it with errors touching Catholic faith and ascetical doctrine. (nn. 7-8)
The same reasoning holds in the case of some persons who are bent on the restoration of all the ancient rites and ceremonies indiscriminately. The liturgy of the early ages is most certainly worthy of all veneration. But ancient usage must not be esteemed more suitable and proper, either in its own right or in its significance for later times and new situations, on the simple ground that it carries the savor and aroma of antiquity. ...It also presents a most satisfying picture of how the whole assembly of the faithful participates in the sacrifice of the Eucharist:
Assuredly it is a wise and most laudable thing to return in spirit and affection to the sources of the sacred liturgy. ... But it is neither wise nor laudable to reduce everything to antiquity by every possible device. Thus, to cite some instances, one would be straying from the straight path were he to wish the altar restored to its primitive tableform; were he to want black excluded as a color for the liturgical vestments; were he to forbid the use of sacred images and statues in Churches; were he to order the crucifix so designed that the divine Redeemer's body shows no trace of His cruel sufferings; and lastly were he to disdain and reject polyphonic music or singing in parts, even where it conforms to regulations issued by the Holy See. ...
[U]nwise and mistaken is the zeal of one who in matters liturgical would go back to the rites and usage of antiquity, discarding the new patterns introduced by disposition of divine Providence to meet the changes of circumstances and situation. This way of acting bids fair to revive the exaggerated and senseless antiquarianism to which the illegal Council of Pistoia gave rise. (nn. 61-64)
The august sacrifice of the altar is, as it were, the supreme instrument whereby the merits won by the divine Redeemer upon the cross are distributed to the faithful... It is, therefore, desirable, Venerable Brethren, that all the faithful should be aware that to participate in the eucharistic sacrifice is their chief duty and supreme dignity, and that not in an inert and negligent fashion, giving way to distractions and day-dreaming, but with such earnestness and concentration that they may be united as closely as possible with the High Priest, according to the Apostle, "Let this mind be in you which was also in Christ Jesus." And together with Him and through Him let them make their oblation, and in union with Him let them offer up themselves. ...Pope Pius XII then goes on to mention the other ways in which people "take part ... more fruitfully in the Mass", such as responding "Amen" to the final doxology of the Canon, becoming familiar with the Roman Missal, when they "answer the priest in an orderly and fitting manner", etc. (nn. 104-105). But he also points out that such participation (a "dialogue" Mass) is not necessary for the action of the liturgy to be a "public act". (n. 106) By pointing out that some people are not able to use the Roman Missal (even when translated into the vernacular), he shows that it is not necessary for everyone to participate at the same level in order to benefit from its fruits: "On the contrary, they can adopt some other method which proves easier for certain people; for instance, they can lovingly meditate on the mysteries of Jesus Christ or perform other exercises of piety or recite prayers which, though they differ from the sacred rites, are still essentially in harmony with them." (n. 108)
The fact, however, that the faithful participate in the eucharistic sacrifice does not mean that they also are endowed with priestly power. It is very necessary that you make this quite clear to your flocks. For there are today, Venerable Brethren, those who, approximating to errors long since condemned teach that in the New Testament by the word "priesthood" is meant only that priesthood which applies to all who have been baptized...
Moreover, the rites and prayers of the eucharistic sacrifice signify and show no less clearly that the oblation of the Victim is made by the priests in company with the people. For not only does the sacred minister, after the oblation of the bread and wine when he turns to the people, say the significant prayer: "Pray brethren, that my sacrifice and yours may be acceptable to God the Father Almighty;" but also the prayers by which the divine Victim is offered to God are generally expressed in the plural number...
[T]here is also a more profound reason why all Christians, especially those who are present at Mass, are said to offer the sacrifice. ... Now the faithful participate in the oblation, understood in this limited sense, after their own fashion and in a twofold manner, namely, because they not only offer the sacrifice by the hands of the priest, but also, to a certain extent, in union with him. ... [T]he conclusion that the people offer the sacrifice with the priest himself is not based on the fact that, being members of the Church no less than the priest himself, they perform a visible liturgical rite; ... rather it is based on the fact that the people unite their hearts in praise, impetration, expiation and thanksgiving with prayers or intention of the priest, even of the High Priest himself, so that in the one and same offering of the victim and according to a visible sacerdotal rite, they may be presented to God the Father. ...
In order that the oblation by which the faithful offer the divine Victim in this sacrifice to the heavenly Father may have its full effect, it is necessary that the people add something else, namely, the offering of themselves as a victim. ... But at that time especially when the faithful take part in the liturgical service with such piety and recollection that it can truly be said of them: "whose faith and devotion is known to Thee," it is then, with the High Priest and through Him they offer themselves as a spiritual sacrifice, that each one's faith ought to become more ready to work through charity, his piety more real and fervent, and each one should consecrate himself to the furthering of the divine glory, desiring to become as like as possible to Christ in His most grievous sufferings. (nn. 79-99)
Further on, he writes about the liturgical year and how, with its "suitable ways and methods in which [it] proposes the life of Jesus Christ for our meditation, the Church gives us examples to imitate, points out treasures of sancticty for us to make our own, since it is fitting that the mind believes what the lips sing, and that what the mind believes should be practiced in public and private life." (n. 153, cf. nn. 154-161)
Towards the end, he exhorts his Venerable Brethren that, "after errors and falsehoods have been removed, and anything contrary to the truth or moderation has been condemned, [to] promote a deeper knowledge among the people of the sacred liturgy so that they more readily and easily follow the sacred rites and take part in them with true Christian dispositions." (n. 186) The Pope also requests (as did his predecessor Pope Pius XI in Divini Cultus in 1928) that "Gregorian chant be restored to popular use in the parts proper to the people" so as to facilitate pious assistance of the congregation at the Mass. (n. 192)
This document sheds light on Sacrosanctum Concilium, the Constitution on the Sacred Liturgy penned at the Second Vatican Council. It gives us a better idea of the type of "actual participation" the Church desires of its congregation: not something manufactured, shallow, or ephemeral, but something organic, contemplative, and timeless. The encyclical commands of us a deep respect for the "august sacrifice of the altar", through which "the work of our redemption is continued, and ... its fruits ... imparted to us".