What Is Plainchant? A Single Line Sung for Fifteen Centuries

Plainchant, also called plainsong and in its Roman form Gregorian chant, is monophonic liturgical music: a single unaccompanied melodic line, sung in unison, with a free rhythm following the natural stresses of the Latin words rather than a metrical pulse. It exists to deliver a text in worship, which explains most of its features. Melodies are classified in the eight church modes, scale patterns each with a characteristic final note and reciting tone, which give chant its distinctive sound to ears trained on major and minor. Settings are described by how many notes fall on each syllable: syllabic chant gives roughly one note per syllable and suits long texts that must be got through, neumatic gives a few, and melismatic extends a single syllable over many notes, reserved for moments of emphasis such as the alleluia, where the final syllable can run for dozens of notes.

The origins lie in the psalm singing of Jewish worship and in the practices of the early Christian communities, developed over centuries in different regional traditions across the Latin West, including Ambrosian chant in Milan, Mozarabic chant in Spain, Gallican chant in Francia and Old Roman chant in Rome itself. What is now called Gregorian chant emerged from the Carolingian effort in the eighth and ninth centuries to standardise liturgy across the Frankish empire on the Roman model, which produced a fusion of Roman and Gallican material rather than a straight adoption. The attribution to Pope Gregory the Great, who died in 604, is legendary rather than historical: the story that the Holy Spirit dictated the melodies to him in the form of a dove was promoted to give the new standard the authority of antiquity, and the repertoire took its familiar shape well after his lifetime. Whether Gregory organised anything of the sort is doubted, though the name has stuck for over a thousand years.

The Carolingian project needed chant to sound the same everywhere, and memory across an empire was not reliable, which forced the invention of notation and set off a chain of consequences:

• •The earliest neumes, from the ninth century, were marks above the text showing the shape of the melody, whether it rose or fell, as a reminder for a singer who already knew the tune
• •Heightened neumes placed those marks at varying heights to show how far the melody moved, which made the contour more precise
• •A drawn line representing a fixed pitch made the heights unambiguous, and Guido of Arezzo in the eleventh century promoted a staff of several lines, the direct ancestor of the modern one
• •Guido also devised solmisation, naming the notes of a hexachord with syllables taken from a hymn, which is the origin of the sol-fa system still used to teach singing
• •With pitch fixed on paper, singers could learn unfamiliar music without a teacher, which made composition as a written activity possible
• •Adding a second line against the chant, called organum, began the development of polyphony, and rhythmic notation followed because independent lines have to be coordinated in time

Chant was gradually displaced by polyphony from the late Middle Ages, survived in reduced and often corrupted versions through subsequent centuries, and was scholarly rescued in the nineteenth century by the monks of Solesmes in France, who compared early manuscripts to reconstruct earlier readings and developed an influential, and now debated, theory of how the rhythm should flow. Their editions became the basis of modern chant books. The Second Vatican Council in the 1960s permitted vernacular liturgy, which drastically reduced the everyday use of Latin chant while formally affirming its primacy, and it survives in monastic communities, in cathedrals and in a specialised concert repertoire. A recording of chant by Spanish monks became an unexpected international bestseller in 1994, which says more about what listeners wanted from it than about liturgy. Its influence persists structurally rather than only historically, since the modes, the notation, the idea of setting a fixed text to a shaped melodic line and the practice of singing in unison all descend directly from it.

Plainchant is a single unaccompanied vocal line in free rhythm, built on eight church modes and shaped to carry Latin liturgical text, with settings ranging from one note per syllable to long melismas on a single vowel. The Gregorian repertoire came from Carolingian standardisation in the eighth and ninth centuries rather than from Pope Gregory, whose authorship is legend. The need to make it uniform across an empire drove the invention of notation, from contour marks to Guido's staff, which in turn made polyphony and written composition possible.