Gregorian Chant, or Western Plainsong,
is the official liturgical music of the Western Christian Church,

and comprises the large body of its traditional ritual melodies

(see the words of the pontiffs below).

Gregorian Chant is foundational to Western Music,
reaching its zenith between 800 and 1200AD.
As an authentic genre it is monophonic,
i.e. sung without harmonies and generally with a free unmetered melody.
The text should be in Latin, and may be in any one of several forms, e.g. antiphons, hymns.

Early History

The roots of Gregorian Chant go back to the psalms which early Christians probably sang in the Hebrew style.
In the fourth century followers of Christ sang hymns to popular melodies
at the same time that a repertoire of Christian antiphons was developing.
The association of Pope St Gregory I (d.604) with the ecclesiastical chant of Rome
existed amongst monk musicians of the Carolingian Period (750-900).
It is now believed that a formal schola cantorum, or school of liturgical singing,
and the formation of a cycle of chants for the liturgical year,
were not achieved in Rome until the late seventh century.
Other cities of Western Europe established their own scholae in the years that followed.
The Carolingian monks attempted to classify the chants into tones, or modes,
and contributed to the development of the medieval modal system.
The modal system, therefore, was fitted over an existing body of chants.
Neumes, or signs and symbols for melodies, also developed from c.800.
From the eleventh century the neumes were gradually replaced by four-lined notation.
This replacement, however, involved the loss of rhythmic indications. 
The authentic chant rhythm was recovered by 20th century scholars, particularly by Dom Eugène Cardine of the monastery of Solesmes (website, through photographic research into Gregorian Semiology.  
Musical and Liturgical Qualities

While the chant repertoire is extremely varied, with pieces for celebration, for mourning, and for contemplation – all well suited to particular human needs – the predictable prayer-forms offer a type of security
that can leave the soul at peace.
Thus the chant has healing possibilities for those who sing it, and those who hear it. The repertoire is a spiritual and literary treasure-trove that brings a sense of the sublime not always found in other musical genres.
So it is not surprising that it retains its popularity to this day.
The liturgical movement that accompanies some of the chant forms is also suited to the prayer.
Sung prayer fills the architectural spaces and carries further than the spoken word.
It is arresting to those who hear it, and who are thus more likely to “get the message” through listening.
While the monophonic aspect of the genre requires discipline and concentration,
some of the chant melodies are so beautiful one can be caught up in the reflection of the phrases.

What some of the popes have said about Gregorian Chant:

 Pope St Pius X: “(Gregorian Chant) is the only chant the Church has inherited from the ancient fathers which she has jealously guarded for centuries... and which she directly proposes to the faithful as her own.”

Tra le sollecitudini 1903.


Pope Pius XII: “Gregorian Chant is the... proper and principal music of the Roman (Catholic) Church... it is preferable to use it as against other kinds of sacred music.”

On Sacred Music and the Liturgy 1958.


Vatican II: “The Church acknowledges Gregorian Chant as specially suited to the Roman liturgy, therefore, other things being equal, it should be given pride of place in liturgical services”

Sacrosanctum Concilium 116. 1963.


Pope Benedict XVI: “It is possible to modernise holy music, but it should not happen outside the traditional path of Gregorian chants or sacred polyphonic choral music."

At a Sacred Concert 2006.