Gregorian Chant

   Repertory of chant most closely associated with liturgies of the Roman Catholic Church. In Richard Crocker’s strict definition, this repertory includes about 600 propers for the mass whose earliest sources date from about 900 and originate in northern Europe. Other scholars would include propers for the divine office whose sources are slightly later. Common usage also includes ordinary chants for the mass composed later still, and even more casual usage would include medieval tropes and sequences, neo-Gallican chants of the 17th century, and any piece published in books authorized by the Vatican such as the Liber Usualis. The name Gregorian comes from a Carolingian attribution of the chant, no longer credited, to Pope St. Gregory the Great, who is depicted in medieval iconography writing music dictated to him by a dove representing the Holy Spirit.

   Ninth-century documents report that Gregorian chant came from Rome when the Carolingian monarchs Pepin I (ruled 741–768) and Charlemagne (ruled 768–814) ordered the liturgies of their kingdom to conform to those of the Eternal City. The few surviving chant books from Rome itself, however, dating from the 11th century, record many of the same texts as the northern sources but different melodies, now known as Old Roman chant, and so there is considerable uncertainty as to whether the northern chant is really Roman, or whether the northern authorities merely wished it to be known as such, whether the Old Roman chant evolved greatly in the intervening two centuries, etc.

   Tenth-century sources show a steady accretion to the Gregorian repertory. First the propers of the divine office appear shortly after those for the mass (the Hartker Antiphoner, c. 1000). Then come multiple settings for the ordinaries, then tropes and sequences. Feasts newly added to the liturgical calendar required their own proper chants. The style of later chants naturally evolved and responded to other musical developments, above all polyphony, which began by adding simultaneous melodies at a fixed harmonic interval above or below the chant. As the originating tradition became ever more distant, verbal accents were made to conform with contemporary tastes, melismas were removed, and the rhythm acquired a meter in performance. A number of French dioceses created entirely new chants near the close of the 17th century, known as neo-Gallican chants, some of which remain popular members of the "Gregorian" repertory today.

   In 1837 Prosper Guéranger became abbot of the Benedictine monastery of St. Pierre at Solesmes, France, which he established as a center for the recovery of both the music and the performance tradition of Gregorian chant. His monks collected and copied ancient manuscripts from all over Europe. Dom Joseph Pothier (1835– 1923) adapted an easily legible square notation from 14th-century manuscripts, and a modern edition of the mass propers, Liber Gradualis, was published in 1883. While the pitches of the melodies seemed settled, their rhythmic quality was not. Finding a uniform length for each note unpalatable, Dom André Mocquereau (1849– 1930) devised a system of three rhythmic signs that he believed recaptured the chant’s subtlety: the dot to double a duration, the episema to lengthen it by an unspecified amount less than double, and the ictus to indicate a stress. Fiercely controverted among scholars, this "Solesmes method" nevertheless spread through recordings and new editions that included Mocquereau’s signs, including the {}Liber Usualis, first published in 1896, the most widely used chant book in history. It also inspired a concerted effort to teach chanting in parishes and schools from about 1920 to 1960.

   The words of the oldest Gregorian chants are almost always sentences taken from the Bible, usually the psalter. (Entire psalms were sung to chanting formulas called psalm tones.) Chants for the divine office included hymns of medieval poetry. Ordinary texts for the mass came from a variety of Biblical and other sources (see MASS). Later medieval chants such as tropes and sequences could be litanies or devotional poetry.

   Gregorian chant plays an essential part in the history of Western music if only because the Carolingian imposition of liturgical uniformity led to the invention of a musical notation. The earliest chant books with musical notation (St. Gall Codex 359 and Laon MS 239, both c. 900) record staffless neumes (notes) that indicate melodic direction but not precise intervals. Neumes on staves date from c. 1000. Scholars have speculated recently that the staffless neumes recorded a local performance of the rhythm, given that the melodies were already known by heart through oral tradition. Following the lead of Dom Eugène Cardine, Rupert Fischer and Marie-Claire Bellocq collated the notations of St. Gall and Laon with modern square notation in the Graduale Triplex (1979).

   See also Cecilian Movement; Council of Trent; Guido D’Arezzo; Medicean Chant; Tra Le Sollecitudini.