Artificial intelligence to recover 4,000 Gregorian chants forgotten for a thousand years | Culture

“Kyrie eleison! / Christe eleison!” (Lord, have mercy / Christ, have mercy)… More than a thousand years ago, monks from different abbeys and monasteries in Europe recited their prayers throughout the day singing. Eight times, every three hours: Matins, Lauds, Prime, Terce, Sext, None, Vespers, and Compline, aided by manuscripts containing neumes (musical signs), the lyrics, and how to sing, solemnly, declaiming. It happened in the Middle Ages, so many times painted black by wars, plague and famine, but also luminous, thanks to cathedrals and codices. Just a blink of an eye later in history, at the end of the 19th century, the monks of the Solesmes Benedictine Abbey, in northwestern France, began taking photos of volumes with Gregorian chants created between the 9th and 11th centuries. A work that they developed in their house and in those of other monks of a good part of the continent. The religious of Solesmes feared that, once again, times of war, fire and destruction were coming. They were not wrong in their omens, a few years later a world war broke out.

The last leap in this story leads to 2023, when a European Commission project, Repertorium, headed by the University of Jaén, is collecting those images of the chants that were photographed by the French monks. A job in which, thanks to artificial intelligence, they will be able to check if these songs are already registered in databases, hallelujah, or if they are not. In this case, they will be able to transfer them to sheet music so that they can be interpreted by Gregorian groups and be recorded so that we can listen to them on a CD or in an application, hallelujah. In addition to Spain, France, Germany, the Netherlands, Italy (Milan Polytechnic), the United Kingdom (Oxford University), Finland (with a group of experts in sound processing) and Lithuania (National Philharmonic Orchestra) participate in this programme.

Julio Carabias He is the researcher who coordinates Repertorium, an initiative that “promotes the cultural heritage and the arts” and “preserves the European musical heritage,” he says by phone. “Sixty proposals from all over the European Union were presented and three were chosen, each one financed with three million euros. One is Repertoire”. It is an idea born from the Department of Telecommunications Engineering of the Higher Polytechnic School of Linares, belonging to the University of Jaén, in collaboration with the company Odratek (Netherlands).

If all those photographed Gregorian chants had to be cataloged by hand, it would take a lot of time and money. “Some 400,000 negatives are preserved.” Logically, not all in good condition. “We are digitizing this material, that is simple, but we also extract all its information (melody, ritual, texts, position in the liturgy) thanks to AI through a system called deep learning (deep learning)”. Subsequently, it will be verified if that song is already cataloged in the digital music libraries that exist on the Internet. “If it doesn’t exist, then it is a historical material that we will recover,” explains Carabias. Among those negatives, in addition to those of Solesmes and other places in France, “there are those of Spanish and German abbeys.” The promoters of Repertorium emphasize that the resulting technology will be open source so that it can be used with other musical modalities.

The Solesmes monks themselves, who have a Paleography workshop to study their historical material, “have estimated that some two million pieces of Gregorian chants will come out of those 400,000 negatives, which are the ones we will compare to find out if they are registered.”

But not everything is as easy as it may seem. This AI needs people to train it to think like a human being. This task will involve the Complutense Institute of Musical Sciences (Iccmu) —founded in 1989 and directed by Álvaro Torrente—, and the University of Alicante. Torrente explains that a musicologist from Iccmu “will help to catalog the photographed songs.” “You have to keep in mind that they are manuscripts from different copyists and times.” Some 127,000 songs will be manually cataloged to teach this AI. French clergymen estimate that “in the end there will be about 4,000” who will come back to life, songs that probably have not been performed in centuries and of which there are no copies.

The next step will be, finally, to be able to listen to them again. “It is planned that in the abbey of Santa María Magdalena de Le Barroux (southeastern France) about 2,200 hours will be recorded and a concert will be given at the end of 2025,” Carabias emphasizes. In addition, all these new songs will be incorporated into an existing application, called Neumz, “a kind of Gregorian Spotify”, points out the researcher. There will also be workshops, conferences and publications. However, all this happens “when the Gregorian is not experiencing his best moment because there are few people in religious orders,” says Juan Carlos Asensio, president of the Hispanic Association for the Study of Gregorian Chant, created in 2002 and participant in Repertorium.

Every Tuesday, Asensio and the other 13 members of the choral group that he directs, Old School, with four decades of history, rehearse in the church of Montserrat, in Madrid: “Do-mi-niii!, do-mi-niii!” Asensio remarks to his companions before singing that part together. Schola Antiqua is among the groups in charge of interpreting the songs that are recovered for recording, as will happen in the monastery of Santa María del Parral (Segovia).

Asensio explains that “all religious rituals have historically had a sung expression to address their divinity.” “Gregorian music emerged in the 8th century, as a fusion of different repertoires that existed in Europe after the fall of the Roman Empire. It is known that at the coronation of Pepin the Short (King of the Franks, father of Charlemagne) in 754, the Pope’s choir sang at the ceremony held in Reims. The king liked it so much that he decided that from then on it should be interpreted, and the singers of Gaul adapted their repertoire to the taste of their monarch, mixing it with the autochthonous ”. It was Charlemagne who led to the great diffusion of the Gregorian, characterized by having a single melody, on the back of the empire that he forged. “It arrived in Spain at the end of the 11th century, with the Council of Burgos, which changed the Visigothic rite for the Gregorian one. Medieval documentation indicates that the choirs were made up of five or six soloists and the rest of the community did not have to have good voices.

In those times, the most common name for this musical manifestation was “plainchant”, adds Asensio, “but they ended up taking that of Pope Gregory I (died in 604, known as San Gregorio Magno), who, by the way, suffered from chronic hoarseness”. “In the mid-19th century, with the rediscovery of Antiquity, they began to study the manuscripts of the songs to interpret them in the most faithful way because logically there were no recordings. In addition, in each monastery it could be done in one way. A German does not pronounce Latin like a Spaniard ”, he details. This religious music was maintained until the Second Vatican Council (1962-1965), when the liturgy was changed and Latin was relegated.

What is sung in the Gregorian? “The basis is the book of psalms,” he continues. “There are 150 poems from the Old Testament, which represent around 85% of the repertoire. There are also texts from the New Testament, words of Christ are repeated, poems by medieval authors… The repertoire consists of several thousand pieces, but in the liturgy some 3,000 are sung between masses and services”. Fans can listen to them in Spain, among other places, in the monastery of Leyre (Navarra), Santo Domingo de Silos (Burgos), Cuelgamuros (Madrid), Poblet (Tarragona), in its Cistercian variant; Montserrat (Barcelona) and a female one, San Pelayo (Oviedo).

As for the best preserved Gregorian, Torrente stresses that “some of the most important manuscripts are in France and Switzerland.” And he emphasizes: “Music was transmitted by heart, later, in churches or cathedrals, the great hymns were copied. It was a Europe that could not be conceived without this kind of music”.