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Good morning Father,

Since I have a passion for liturgy and popular piety, I would like to ask you something about the Forty Hours’ Devotion, a common exercise of devotion here in Italy that is practiced in my parish starting from Palm Sunday.

I’ve read that they are regulated by the Clementine Instruction; however, I couldn’t find it anywhere. Can you help me?

Thank you, I wish you a good Holy Week!


Dear reader

I could not find any information regarding the Clementine Instruction. However, I was able to recover a brief summary from an ancient dictionary of the liturgy. I will transcript it here for you and for all who are interested. I have to say, the desire for decorum and respect towards the Blessed Sacrament that is shown is impressive.

“The Clementine Instruction, named after Pope Clement XII who promulgated it in 1731, contains all the rules that should be followed when the Blessed Sacrament is solemnly exposed for the Forty Hours. 

2. The history

The Forty Hours are one of the many forms of Eucharistic Exposition that originated from the late Middle Ages. At the beginning of the XVI century, they were the most common form of solemn Eucharistic adoration in Italy. They owe their name to the forty hours that Our Lord spent in the tomb; its origin might be traced back to the adoration that, in the Holy week from Thursday to Friday, was done before the reposition of the Sacrament, erroneously called “the tomb”.

The Forty Hours were prayed for the first time in Milan in 1527, a devotion introduced to prevent the wars of that time under the impulse of Gian Antonio Bellotti, who was granted permission to exercise this practice four times per year. For that occasion, the Sacrament was not exposed, and the act of adoration occurred before the closed tabernacle. It is disputed when the exposition of the Blessed Sacrament began, with great attention to lighting and decorations. It probably started in Milan: perhaps in 1534, thanks to P. Bono da Cremona, a religious Barnabite; or maybe it was the Capucine Giuseppe da Fermo in 1537. Either way, we owe the latter the diffusion of this practice as well as the tradition of passing the exposition of the sacrament through all the churches of the city, to make the adoration last for the whole year (perpetual adoration).

Pope Paul III assigned the first indulgences to whoever did this practice, and it became a stable event in Milan by the will of Saint Carlo Borromeo, as it is stated in the first Provincial Council of 1565.

Saint Filippo Neri was a great supporter of this devotion and established it as one of the main practices of devotion in his confraternity; the solemn exteriority that accompanied this practice contributed to making him the father of the musical oratorio (and these institutions played an important role in embellishing the music of that time).

In 1952, Pope Clement VIII regulated this practice, requiring that the exposition of the Forty Hours became “an interrupted chain of prayers, at every hour of the day, all year long” to be established in Rome. Eventually, it was Clement XII who, in 1731, established a precise ritual for the celebration of the forty hours, hence the name “Clementine instruction“.

The Forty Hours, as defined in the Clementine instruction, should be practiced solely in those cities that have many churches. However, this devotion spread in minor towns as well, at least as an annual practice; especially after what happened in Macerata in 1556, when two Jesuit missionaries prepared a particularly solemn celebration of the forty hours to divert the people’s attention from an immoral show. It was a success that contributed to enhancing the sense of expiation associated with the practice, particularly in those places where the Forty Hours occur once a year (usually during the period of carnival). Finally, in 1897, Pope Leo XIII extended to all the churches in the world the indulgences that were traditionally conceded to those who did that pious practice in Rome.

3- Content of the Instruction:

The Instruction is divided into 37 paragraphs, briefly analyzed below:

General rules (I-VI) An exterior sign should be exposed at the main entrance of the church. The altar should be clear of any relics or funeral symbols. The decorations are white; the monstrance is in plain sight. There should be no flowers before the Tabernacle and it is preferable that at least twenty candles burn constantly on the altar. 

Dressing code for clerics and lay people  (VI.X) One or two clerics must wear the surplice (or cotta) while adoring the Sacrament. Wearing the stole is not necessary. The cleric holding the lamps must also be dressed with the surplice. Lay people cannot enter the presbytery unless necessary (i.e., in order to replace a cleric). In this case, the lay person shall also wear a surplice. Genuflection on both knees is required when entering or exiting the presbytery, as well as when passing before it.

Celebration of Mass (XI-XIX; XXV-XXXV). The votive Mass for the Blessed Sacrament can be celebrated at the altar of the exposition only on the first day (before the Blessed Sacrament is exposed) and on the third day, for the reposition. These two days (1st and 3rd) the celebrated Mass is called “votive mass of the Blessed Sacrament”. It is celebrated with the sacred ministers.

On the other days, the Mass of the day will be celebrated, with the memory of the Blessed Sacrament in its conclusion. On the second day, the votive mass will be celebrated, pro pace or for another necessity, according to the prescriptions of the bishop. It is specified that this mass should not be celebrated either at the altar of the exposition or at every other altar where the Blessed Sacrament is exposed. During the whole period of time of the 40 hours’ devotion, it is not possible to celebrate requiem masses. The antependium (the front cover of the altar) is white.

Ceremonial of the Mass for exposition. During the Mass of the first day, the celebrant consecrates two large unleavened hosts, one of which will be later used for the exposition. The monstrance with the Blessed Sacrament is placed on the corporal, right after the priest received communion.

While the Blessed Sacrament is exposed, it is prohibited 1) to play the altar bell neither during private, nor solemn masses; 2) to make the Collect; 3) to use the biretta and the stole during the homily; the homily should be kept short.

After the last Gospel, the celebrant wears the cope, incenses the Blessed Sacrament and receives the white humeral veil. The deacon genuflects at the predella, takes the monstrance (or ostensory) and gives it to the celebrant, who’s on his knees. The choir sings the hymn attributed to St. Thomas Aquinas “Pange lingua gloriosi corporis mysterium, and then the procession begins.

Procession of the Blessed Sacrament (XX-XXIV) The confraternities walk before the clergies; the latter is preceded by the crucifer, dressed with a surplice (not a tunicle) and accompanied by two acolytes.

Eight priests or clerics walk before the canopy. Every head must be uncovered; it is not permitted to wear a zucchetto, not even due to health reasons. The candle must be brought on the external hand. All priestly vestments must be white. Children shouldn’t represent any saint. Authorities can take the canopy poles only when outside of the church. 

The Blessed Sacrament must be incensed constantly;  the celebrant priest, even if he’s a bishop, has to bring the monstrance with his hands. The procession must proceed on foot. The bells of the church where the exposition occurred must ring. Similarly, whenever the procession passes by another church, the church’s bells must also ring.

If the procession is particularly long, the Blessed Sacrament can be reposed for some time in altars specifically built on the pathway.

After the procession, the deacon receives the monstrance and takes it to the altar for exposition; then everybody sings the Tantum Ergo (the incipit of the last two verses of Pange Lingua) as the celebrant is incensing. 

Other expositions (XXXVI) Other expositions of the Blessed Sacrament can be public or private, more or less solemn. During private expositions, the ciborium should not be taken off the tabernacle, it suffices to open its door. It is also possible to incense the Blessed Sacrament”.

I rejoice in your great passion for the Church Liturgy, a beautiful gift you received from the Lord.

I bless you and will remember you in my prayers.

Father Angelo