Liturgical reforms of Pope Pius XII
The liturgical reforms of Pope Pius XII continued a process initiated by Pope Saint Pius X, who began the process of encouraging the faithful to a meaningful participation in the liturgy. Pope Pius XII redefined liturgy in light of his previous encyclical Mystici corporis and reformed several liturgical practices in light of this teaching. The liturgical teaching of Pius XII is contained especially in his encyclical Mediator Dei of 1947. Although Pius XII felt compelled to reprove the desire for novelty among certain leaders of the Liturgical Movement, the liturgical reforms undertaken later in his pontificate were in fact relatively broad in their scope.
Until Pius XII, the Church celebrated Mass always in the mornings, as a reflection of the original sacrifice of Jesus Christ. In light of the displacement and persecution in much of Europe during World War II, evening Masses were permitted on a provisional basis. They turned out to be popular, opening the Church to new publics.
To allow for the faithful to receive Communion at Masses in the evening and at other times, Pius XII decreed several changes to regulations regarding the Eucharistic fast. Prior to 1953, Catholics were required to abstain from consuming any food from midnight before receiving Holy Communion. This requirement to fast from midnight was changed by the Apostolic constitution Christus Dominus, issued in 1953, by which, the fasting period was reduced to three hours from solid foods and one hour from liquids before communion. Water or medicines did not break the fast.  Four years later, in the Motu Proprio Sacram Communionem, the fasting requirements were further reduced.
Liturgical use of the vernacular
Combining continuity and innovation, the reforms made under Pius XII to the sacred Liturgy helped to prepare the way for the more dramatic liturgical reforms that would follow the Second Vatican Council (1962–1965), though it is unclear how far Pope Pius XII himself intended these reforms to go. One goal of the liturgical magisterium of Pius XII was to restore a more reverential atmosphere within Church buildings. The use of vernacular language, cautiously favoured by Pope Pius, was hotly debated at his time. He increased non-Latin services, especially in countries with expanding Catholic mission activities. Though insisting on the primacy of Latin in the liturgy of the Western Church (cf. Mediator Dei, par. 60), the pontiff did nevertheless approve the use of the vernacular in the Ritual for sacraments and other rites outside the Mass. All such permissions, however, were to be granted by the Holy See, and Pius XII strongly condemned the efforts of individual priests and communities to introduce the vernacular on their own authority.
In 1948 the pope erected a Pontifical Commission for the Reform of the Liturgy. Monsignor Annibale Bugnini, who served until the pontificate of Paul VI, under whom he drafted the revision of the Ordinary of the Mass and the whole of the Roman Missal, was appointed secretary of this Commission.
New Liturgical Propers and other directives
Following in the footsteps of his predecessors, Pius XII instituted a number of new feasts and approved new Propers. After defining the Dogma of the Assumption in 1950, a new mass formula (the mass Signum magnum) was introduced for the feast, which falls on August 15. Pius XII also instituted the feast of the Immaculate Heart of Mary, which he established as a double of the second class and fixed to August 22, the octave day of the Assumption. Other new feasts included the feast of the Queenship of Mary (May 31) and the feast of Saint Joseph the Worker (to coincide with the socialist holiday of May 1), which thus replaced the Feast of Saint Joseph Patron of the Universal Church, observed until then (from 1870) as a movable feast on the third Wednesday after Easter. Pius XII added to the missal and breviary a new Common of Holy Pontiffs, in order to highlight the special role of the Roman pontiffs in the economy of the Church. Until then, holy popes had been commemorated liturgically using the same texts as other bishops. The new mass for holy pontiffs begins with the Introit Si diligis me.
The Sacred Congregation of Rites had jurisdiction over the Rites and ceremonies of the Latin Church such as Holy Mass, sacred functions and divine worship. It issued the location of the blessed sacrament within the Church, to be always at the main altar in the centre of the Church. The Church should display religious objects, but not be overloaded with secondary items or even Kitsch. Modern sacred art should be reverential and still reflect the spirit of our time. Since 1942, Priests are permitted to officiate marriages without Holy Mass. They may also officiate confirmations in certain instances.
Revised Easter Vigil
In 1951, on an ad experimentum basis, Pope Pius XII introduced the Easter Vigil, a new celebration of Easter night  by means of De Solemni Vigilia Paschali Instauranda. This has been highlighted as his most important reform, as the Easter ceremonies are the centre of all Christian faith and life. In ancient times Christians had baptised neophytes during a night-long Vigil preceding Easter Sunday. The celebration concluded after dawn by the offering of Mass. In time this Mass became the Mass of Easter Sunday, which was separated from the observance of the liturgical end of Lent, the Easter Vigil, itself being anticipated on the morning of Holy Saturday. This practice of celebrating the Vigil on the morning of Holy Saturday was in place by the twelfth century, after the hour of the liturgical observance had already been moved back bit by bit over preceding centuries. Pius XII restored the older time for the observance of the ceremonies, but most importantly created a dramatically restructured form of the ceremonies. His re-introduction of the Easter Vigil was generally popular, although it faced a cool reception from prelates like Cardinal Siri of Genoa and Cardinal Spellman of New York. Other Christian denominations adopted the popular Roman Catholic Easter ceremonies in later years, an ecumenical influence of Pius XII. The new Easter Vigil reduces the number of prophecies (Old Testament passages read before the blessing of the font and the Mass) from twelve to four. The rite for blessing the Paschal Candle was also changed: formerly the deacon would process into the church with a triple-branched candlestick known as the arundo (a symbol of the Blessed Trinity), which would be used to light the Easter Candle. With the reform to the Easter Vigil, the Paschal Candle itself is carried in procession and the arundo is suppressed. The Candle is no longer blessed during the singing of the Exsultet, though the liturgical text in question refers to the blessing of the candle. The "renewal of baptismal promises", devised for the new Easter Vigil, introduced into the liturgy of the Mass the principle of vernacularism for the first time.
Liturgical Reforms of 1955
The New Rite of Holy Week
Perhaps the most significant and bold liturgical reform under Pius XII was the promulgation of a new rite of Holy Week, which significantly changed the most important ceremonies in the Roman liturgy. In 1955, four years after the introduction of the new ad experimentum Easter Vigil, Pius XII promulgated new liturgies for Holy Week in the decree Maxima Redemptionis (November 19, 1955). In addition to the new Easter Vigil, described above, the rites for Palm Sunday, Holy Thursday and Good Friday were also greatly modified.
Reform of the rubrics and liturgical calendar
The rubrics and calendar of the Mass and the Divine Office were reformed by the constitution Cum hac nostra aetate (March 23, 1955). The reform to the calendar, the most dramatic before its complete overhaul in 1969, consisted mainly in the abolition of various octaves and vigils. An octave is the week-long prolongation of a great feast, either by the celebration of a proper Mass all through the Octave or by the addition of an additional Collect when the Mass of another feast is celebrated. Of the 18 octaves existing in the Roman calendar, all but three (Easter, Pentecost, Christmas) were purged in the reform, including the octaves of the Epiphany, Corpus Christi, the Ascension and the Immaculate Conception. A vigil is a day of liturgical preparation preceding a great feast. The reform of 1955 eliminated roughly half the vigils in the Roman calendar, including the vigil of the Epiphany and the vigils of the Apostles.
The ancient custom of beginning a feast with first Vespers on the eve of the feast was abolished, with certain exceptions. Following the reform, most feasts have only one set of Vespers (what formerly was known as second Vespers), celebrated on the afternoon of the feast itself. The purpose of this derogation of the ancient custom was to simplify the process by which a feast had to be commemorated when the second Vespers of one feast coincided with the first Vespers of the subsequent feast. The reform also abolished the custom whereby Vespers was to be recited before noon during Lent. This custom was a survival of the ancient custom whereby the Lenten fast could only be broken after Vespers; the Church had long since permitted this meal to be taken at mid-day and had thus also anticipated the office of Vespers during Lent.
Proper Last Gospels were also eliminated in the reform, with the exception of the third Mass of Christmas (when the Gospel of the Mass is taken from John 1) and at Low Masses on Palm Sunday. A "Proper Last Gospel" occurs when a commemoration is made at Mass of another feast (or feria or vigil or Sunday) of a high rank, whose Gospel is read at the end of Mass in place of the habitual Last Gospel (John 1: In principio). Prior to the reform of Pius XII, a proper Last Gospel was always said when a feast was celebrated instead of a feria of Lent, or a vigil, or a Sunday.
The manner of ranking feasts was also changed slightly. The reform of 1955 suppressed the rank known as the semi-double, leaving only doubles and simples. All semi-double feasts became simples, and all semi-double Sundays became doubles. (In 1960 John XXIII completely replaced the traditional manner of ranking feasts by abolishing the double, with its various grades, and the simple, and classifying feasts instead as first, second, third, or fourth class.)
Finally, the supplementary prayers formerly recited in connection with the breviary were also suppressed. Thus, for example, the various seasonal Marian antiphons formerly recited at the end of the liturgical hours were retained only after Compline.
In his book The Simplification of the Rubrics, explaining the changes, Monsignor Annibale Bugnini commented, "The present decree has a contingent character. It is essentially a bridge between the old and the new, and if you will, an arrow indicating the direction taken by the current restoration."
- Acta Apostolicae Sedis, (AAS) Roma, Vaticano 1939-1959
- Mediator Dei, Acta Apostolicae Sedis, (AAS) Roma, Vaticano 1947, 521 ff
- Gabriel Bertoniere, The historical development of the Easter vigils in the Greek Church and Related Services, Rome 1972
- Paul Bradshaw, The New Westminster Dictionary of Liturgy and Worship 2005
- AAS 1953, 15-24
- March 19, 1957, AAS 1957
- AAS 1959, 795
- AAS 1944, 44
- AAS 1957, 425
- AAS 1952, 542-546
- 7 16, 1942, AAS, 1942
- AAS 1946, 349-354
- AAS 1956, 153
- AAS 1951, 128-137
- Bradshaw, 162-163
- Bertoniere, 45