St Augustine (354-430) while records in a treatise the set of knowing of his epoch and establishes in addition the rules for the monastic life (St. Augustine's rule), bequeaths us the first one "De musica". Though incomplete as it treats only the rhythm, this work gives impulse to the Christian music. After the example of the teacher, it is possible to study the music. Here the music is related little by little with the science of the cantus. All this demanded time. Augustine was writing at the end of the 4th century, and it will be necessary to wait until 850 even for the work of Aurelian of Regomé, the first erudite clergyman who, knowing the cantus, starts confronting two aspects of his knowledge: practice and theory.

THE CANTUS

The conditions of plainchant development prove to be so far from what might be called a pure musical current. The own nature of this music is opposed to it. It is not composed but reproduced as it has been received. It is not a question of artistic invention but of faithful reproduction of a prototype to which highly respectable virtues of efficacy are attributed. One must not change even one note. Nevertheless, it is necessary to notice that this kind of transmission could have caused serious transformations. St. Irenaeus was already complaining in Lion about forgetting the Greek. It can be thought that the melodies could not survive any more time than the same language. It is not possible too, except in rare cases, to speak about focal point of music. For example, comparison cannot be established between Milan of St. Ambrose and the current city of Salzburg, and have in mind that Milan was the theater of a reform since St. Ambrose imposed there the oriental customs (Ambrosian rite).

In the primitive Church several genres of singing were practiced. The reading of the Old and New Testament always imposes the present cantilatio even in not Christian worships. It is sure that there was later a psalmody, that is to say, singing of the psalms. It is doubted on his melodic precise form, but it is known that the verses were sung with the same melody, be already alternating between two groups, be already without alternation, or with a response consisting of an acclamation of the assembly: it is the responsorial chant, which is anticipated in Plinio the Young letter "Carmen secum in vicem" (61-113) in the year 110.

Hundred years later, Hipolyt of Rome (m. h. 235) indicates that the faithful people answers with a hallelujah to the singing of the psalm done by the deacon. A formula is often repeated: the writers mention that Christians sing psalms, canticles and hymns. One cannot take this expression as a precise description. It is an all purpose Biblical gadget. The canticles are nevertheless certain Biblical passages destined to be sung and they possess the same expression as the psalms. At present we know them still.
The question about the hymns is delicate. According to an ancient expression, the hymn is essentially a chant of praise directed to God or to a god. If one of these elements is absent, there is no hymn. In this sense, the word includes also the psalms and the canticles, of which some of them fulfill three conditions. Anyway, the hymn is not designated as we understand it currently, as a strophic composition without refrain, sung on a popular melody and that appeared with St. Ambrose.

The set, truly, was very simple. The secret and the tact were imposed by the circumstances. Only a case escapes to this silence: that of the devotion to the graves. Actually this devotion was not essentially Christian and the hierarchy censored it frequently. ¨Who were singing so in this church?". The celebrant priest was singing surely his improvised prayers as those of the current preface of the mass. Beside that it is the reader who takes charge of the public reading with melodic declamation of the epistles, gospels and psalms. His feature turns him into a teacher and there are frequent allusions to the psalms he teaches to the attendants. The chantre appears for first time in the Council of Laodicea canons (343-381). Only one in the temple and only in his pulpit is canonically designated by the hierarchy and he does not group around him a numerous schola as it is believed. The schola does not appear in Occident up to the end of 7th century. It is possible to believe that the chantre has not always been part of the clergy. It is not mentioned between the different orders leading to the priesthood, and if he is named there is to indicate that the readers and the chantres are not included in the clergy subject to celibacy (Council of Venice, 463). This chantre is the interpreter of the faithful people who probably answers to his chants as to the invocations of the priest with short acclamations like Kyrie eleison.

Because of the stealthiness of the Church until the 4th century, the unit of the liturgical beginning and of the details that today are familiar to us, cannot be found either in the liturgy or in what is part of the chants. The communities chiefs were free to improvise in many cases, which motivated differences between the local churches and even many heresies. The orientation changes after the Church became free. Occident will tend to a progressive unification, whereas East continues with his local customs as in the past. And so, we find at present numerous rites in East, whereas in Occident the Gregorian Chant has conquered Europe slowly .

In spite of the frequent changes and the reciprocal influences, it must not surprise the entire separation produced in the XIth century between two worlds so differently constructed. The key for the western union was Rome but the work was slow. At first a certain diversity was needed. There were constituted local groups that allowed to feel scarcely his existence in the IVth century. A little time later, the Pope is faced to a Milan group, to a Hispanic group, to the uncompromising Celts in Ireland, to the Gauls attached to his rite and all they are obstinate and defend his personality. These groups existed in the period that spreads from the 4th to 8th centuries and they will be assimilated progressively by Rome: Gallia in the 8th century; Roman-Spain will not be until the 11th century. The Celts evangelized from the 6th century by St Gregory's efforts will resign very slowly to his previous rites, and Milan preserves still theirs.

In the center of the Roman rite the monastic liturgy is emphasized still today in accordance with St Benedict's scheme (Benedictine order), previous to the Gregorian chant. The remaining differences level out in the 16th century after the decisions of Trent council in 1563. The Occident church had to adopt the Roman books. The monastic rites were escaping from this precept and the cities capable of demonstrating that his customs had more than two hundred years of existence might request to preserve them. For practical reasons, the clergy chose for the printed books guaranteed by Rome. Only Toledo, Milan, Braga and Lion asked to preserve his previous rites. These considerations are valid for the music narrowly tied to the text, and because it should be admitted into the Middle age that every church should make, according to his own criterion, the selection of texts. It was not a question of introducing innovations. The election was exercised between the classic and known works such as the list of the hallelujahs of Whitsunday or that of the graduals. Exceptionally some of every church own pieces were destined to the local holidays. Any work music that had his place in the liturgical year had little changes. The list of variants is particular and it does not coincide with those of the neumas (graphical music signs without system representation of musical notation) nor with those of the texts variants.

It is evident that the first symptoms of unification are present from the 4th century. The liturgy of that time becomes abundant and goes to a numerous crowd. One must monitor his content. Every Pope is going to write an annual liturgy: the "circuli anni" canticles that to ourselves does not answer to the title, since the works to sing appear there devoid of any musical configuration. Some of these writings are famous: St. Leo´s Sacramentario Leoniano (440-461), and the Gelasian one, a St. Gelasio work (492-496). These constitute also big stages. None had the luck of Gregorian Chant; St. Gregory´s work (590-604) adopted previous texts, included new contributions but it has not been written in the form in which it has come to us. But it is this precise form the one that has been imposed and the one that has given his name to the chants that impliedly goes with it and that surely not whole or only a small part owes to St. Gregory.

The double history of the text and of the music is difficult to find for the period that goes from the years 600 to 750. The gelasian had spread very much and Gregorian Chant had to join to it. Besides, in this epoch it seems that Rome knows other customs: the old Roman singing, predecessor of Gregorian Chant, and on whose topic is discussed still. One of the customs could be that of the Roman curia and other one that of the churches of the city. Nothing is sure. The old Roman singing, anyway, is represented only by some books and by remains in the liturgy. His aspect shows it less subtle than Gregorian chant but is more prolix and more archaic.