Extract from the General Decree of November 16, 1955, which restored the Liturgy of Holy Week:
Of the weeks in the Church's year, Holy Week is truly singular for the fullness, majesty, and devotion of the ceremonies. From apostolic times special care had been taken to celebrate the central mysteries of our Redemption, and in the course of time three days--Friday, Saturday and Sunday--came to be set apart for the liturgical memory of Christ crucified, Christ buried, Christ risen. A little later was added a fourth day of solemn ritual remembrance of the institution of the most Holy Eucharist. A further addition was made on the previous Sunday, to celebrate the triumphant entry into His holy city of Christ our lord, Messias and King.
Originally these rites were performed at the hour of day at which had occurred the scenes liturgically represented. Thus Mass on the Thursday was celebrated as the Last Supper had been, in the evening; the liturgical action on the Friday took place, as had taken place the climax of our Lord's Passion, in the afternoon; and late on the Saturday evening began the solemn vigil that ended early the first day of the week with the Resurrection.
In the middle ages various causes conspired to bring them forward earlier and earlier into the day, so that eventually they became morning functions, impairing the earlier harmony with the accounts given in the Gospel narratives. This disharmony was most glaring on the Saturday, which became liturgically the day of Resurrection instead of that days' eve, and liturgically again, from a day of darkest mourning became a day of light and gladness.
In the days of faith these three days, the Sacred Triduum, were days of obligation, and the faithful, freed from servile work, were able to take their part in the morning celebrations in great numbers. By the seventeenth century social and religious conditions had altered so greatly that in 1642 the Sacred Triduum was removed from the days of obligation and the three days became officially what they had long been in practice: ordinary workdays. The beautiful solemn liturgy of Holy Week had by this time become unknown to and unappreciated by all save the clergy and a handful of the faithful. A partial remedy was sought by introducing extra-liturgical devotions each evening (Holy hour, Three Hours, Mater Dolorosa sermon, Stations of the Cross); but these lack much of the great dignity and sacramental power and efficacy of liturgical celebrations.
To bring an end to this serious loss liturgists, parish clergy, and Bishops in every part of the world have for long begged the Holy See to restore the liturgical actions of the Sacred Triduum to their proper hours in the evening. This was a serious undertaking, calling for much thought and consultation. In 1951 the Easter Vigil liturgy was restored to late evening by way of experiment, and in 1953 the Apostolic Constitution "Christus Dominus" permitted Mass to be said and Communion to be received in the evening on certain days in the year. From every country the Holy See received reports of greatly increased attendance and fervour. A Commission was appointed to investigate further and propose definite action, and the Sacred Congregation of Rites concurred with the action proposed. The Restored Ordo for Holy Week was published in November 1955. The following prescriptions are noteworthy:
1. The Restored Ordo for Holy Week affects all the faithful of the Roman Rite, but not those who follow other Latin Rites.
2. It takes effect from March 25, 1956.
3. Sunday in Holy Week is officially named: "Second Sunday in Passiontide, or Palm Sunday."
4. Matins and Lauds for Thursday, Friday, Saturday, if sung in common, are to be said in the morning, not the previous evening. (An exception is made for a church where on Thursday the Mass of the Chrism is celebrated).
5. On Thursday and Friday Vespers are omitted, since the liturgical functions of the two days replace them. Compline is chanted in choir after the function.
6. On Holy Saturday the Vigil celebration replaces both Vespers and Compline.
7. The Mass of the Last Supper should not begin earlier than 5 p.m. or later than 8 p.m.
8. Friday's liturgical action should be after noon, preferably about 3 p.m., but the Diocesan Bishop may permit it to begin later, but not later than 6 p.m.
9. The Paschal Vigil should ideally be celebrated after sunset on Saturday evening.
Not only have the times been radically altered, but the ceremonies themselves have been modified. This is mainly by way of shortening and simplification: and the intention is to make the main ideas of each function stand out more clearly. For the most part, these changes are not innovations. They are mainly a return to an older form, more in line with what was known in the days of St. Wilfrid and St. Bede.
The desire of the Holy See in all this is that the Holy Week Liturgy should be celebrated everywhere with the greatest solemnity possible, and that the people should in some way take an active share.
(From the Roman Missal, 1962)