Plainsong rhythm is the free rhythm of speech; it is a prose rhythm, which of course arises from the unmetrical character of the words to be recited—psalms, prayers, and the like.
In character, plainsong falls into two essentially distinct groups—the responsorial (developed from recitation of psalms round a ‘dominant’), and antiphonal (developed as pure melody).
Plainsong developed during the earliest centuries of Christianity, influenced possibly by the mus. of the Jewish synagogue and certainly by the Gr. modal system (see modes). A major reform was instituted in the 6th cent. at, it is said, the request of Pope Gregory.
Further reform was attempted at the end of the 16th cent., but the results were disastrous. Palestrina was charged with the work of revising the plainsong of the Gradual, Antiphonal, and Psalter, but died almost immediately after accepting the commission. Felice Anerio and Soriano undertook the work, and their edn. was pubd. by the Medicean Press in 2 vols., 1614–15. This Medicean Edition, as it is called, with its addition and suppression of melismata, its altered melodies, and its new ones, became the basis for many cheaper performing edns. In the 18th cent. there was a fashion for introducing grace notes and passing notes into the plainsong (called in Fr. machicotage). In the 19th cent. there was another cry for reform and the famous Ratisbon (Regensburg) edns. appeared—unfortunately based on the Medicean Edition. Years of controversy followed, for the Benedictine monks of Solesmes, in Fr., had long been at work in the most scientific spirit, photographing and collating innumerable manuscripts, in all the libraries of Europe. They pubd. their Gradual in 1883 and their Antiphonal in 1891. The Ratisbon edn. had had papal privileges conferred upon it, but in 1903 these expired and in the same year Pius X was chosen Pope and he at once issued his famous Motu Proprio on church mus., laying down, among other things, the importance of plainsong and the necessity of taking it from early and pure sources.
Among the reforms of the Solesmes monks (who, temporarily driven from France by anti-clerical legislation in 1901, carried on their work for some years in Eng.) was the introduction of a lighter and more rhythmic manner of perf.
plainsong or plainchant, the unharmonized chant of the medieval Christian liturgies in Europe and the Middle East; usually synonymous with Gregorian chant, the liturgical music of the Roman Catholic Church.
In the Western church four main dialects of plainsong developed—Ambrosian, Roman, Mozarabic and Gallican—that seem to have been derived from similar sources. Gregorian chant is named for Pope Gregory I, whose credited role in compiling liturgical books during his papacy (590–604) is now considered questionable.
The origins of the chant go back to early Christian times, and it seems to have derived from musical practice in the Jewish synagogue and Greek musical theory. During the late Middle Ages and the Renaissance, and also in later times, the chant melodies were used as the basis for polyphonic composition. In the 19th cent. the Benedictine monks of Solesmes sought to restore the Gregorian chant to its original form and their published editions from 1889 onward became the official music of the Catholic Church. The texts of plainsong are the words of the Mass, the Psalms, canticles, and certain verse hymns.
The tonality of Gregorian chant is based on the system of eight modes (see mode). The notation of the chant evolved into systems of neumes (see musical notation) that were still used in the 20th cent. in preference to modern mensural notation for plainsong. Little is known of the rhythm with which the chants were performed in the Middle Ages. The chants were contained in two principal books: those for the Mass in the "Gradual," those for the Office in the "Antiphoner." The modern Liber usualis is a compilation of most frequently used chants from the two.
See W. Apel, Gregorian Chant (1958); J. R. Bryden and D. G. Hughes, ed., An Index of Gregorian Chant (2 vol., 1969).