Though the church fathers were ambivalent about the place of music in a moral life, music adorned the liturgy of the church as far back as we can trace. One of our early witnesses to plainchant practice with the nun Egeria whose account of her pilgrimage to Jerusalem from ca. 400 A.D. includes descriptions of psalms and singing. Over the next several centuries, the liturgy continued to develop until it took on the format for the mass and office that is familiar to the modern-day student of the medieval church.
This liturgical practice resulted in part from the religious reforms of Charlemagne (ca. 742-814), who drew on the resources of the church in his attempts to unify his empire. He replaced the disparate local and regional varieties of plainchant (such as Gallican, Mozarabic, and the like) with a single practice. According to Charlemagne's biographers, he wisely decided to send to 'the source,' that is to Rome, for the authoritative versions of chant. The resultant liturgical practice--in fact, a combination of Frankish and Roman elements--is commonly known as Gregorian chant, though recent research has shown that the Pope Gregory involved in the creation of the liturgy was likely Pope Gregory II (r. 715-731), rather than Pope Gregory I (r. 590-604) (see McKinnon, pp. 102ff).
The music of the church can be divided into chants for the mass, which combines a celebration of the Word of God and of the Eucharist, and those for the office, a daily cycle of services involving psalms and prayers, though the requiem mass differs from the daily mass in structure, and various processions are technically paraliturgical. Texts which change every day are called proper, while stable texts which repeat over most of the church year (such as the Kyrie, Gloria, Credo, Sanctus, and Agnus Dei) are called ordinary. Chant melodies range from a simple recitational style involving a single pitch (perhaps with some inflections to provide punctuation), through the straightforward chants which any member of the choir could sing, to the extremely elaborate soloistic chants. Melodies are also classified by how many notes there are per syllable: syllabic melodies have one note per syllable; neumatic melodies generally have two to five notes per syllable; and melismatic melodies have elaborate runs of six or more notes decorating several syllables over the course of the piece. Every service has a mixture of these styles, providing dramatic impetus to the liturgical action.
As Carolingian cantors and their successors attempted to grapple with the importation of nearly four thousand chants for the church year, they developed systems for organizing the musical materials involved. The pressures of memorization supported, and perhaps instigated, the development of a notational system, though the familiar square notation of most surviving chant leaves and most modern-day chant books did not develop fully until the late twelfth century. It also encouraged the development of the system of church modes, which classify chants by their range, their final (the central pitch of the melody where the tune usually ends), and their melodic idiom. The spread of liturgical books, with or without notation, likewise helped to regularize liturgical practice across the realm.
The medieval liturgy has been reconstructed in large part due to the efforts of the Benedictine monks of Solesmes Abbey in France, who have issued facsimiles of early chant manuscripts and compiled editions based on those early sources, including the Liber Usualis, which contains chants, prayers and readings for important services throughout the church year. The Latin liturgy itself, however, has been out of favor since Vatican II (1962-65).
Music as a Liberal Art Versus Music as a Practical Craft
Though the modern world considers music a 'sounding art' involving melodies, rhythms, and harmonies, the medieval thinker classified music as a mathematical discipline, part of the quadrivium, along with geometry, arithmetic, and astronomy. The intellectual study of music--speculative music theory--was a study of proportions, whereas aspects of actual performed music treated music as a craft. This bias can be traced back to Boethius (ca. 480-ca. 524) and Martianus Capella (fl. ?early 5th century), whose treatises served as textbooks for much of the Middle Ages. Nevertheless, a body of music theory addressing issues such as mode and, later, rhythm developed.
Throughout the Middle Ages, monasteries and abbeys nurtured music, preserving the quadrivial treatises alongside practical musical sources. The ninth-century library at Reichenau, for instance, boasted copies of works by Augustine, Isidorus, Cassiodorus, and Boethius, as well as ten antiphoners containing music for the Divine Office (see Carpenter, p. 17). St. Gall, too, had a vibrant intellectual life as well as an active musical scriptorium which produced a large number of chant manuscripts in a distinctive musical script. The monastery of St. Martial housed a rich collection of manuscripts containing monophonic and polyphonic additions to the liturgy dating from the tenth to the twelfth centuries. Significant sources also survive from Santiago de Compostela (the Codex Calixtinus which contains music brought by pilgrims to the shrine of St. James), from St. Denis (a royal abbey in France) and from Las Huelgas (a women's convent in Spain with a flourishing choir school where the women evidently performed polyphony). Indeed, most monasteries of any size housed at least a few choirbooks containing the chants for either mass or office.
Additions to the Liturgy, ca. 900-ca. 1100
In the tenth, eleventh and twelfth centuries, composers and performers expanded the liturgy in a number of ways. New feasts were created (with their attendant music for mass and office), and new music created for chants of the ordinary. Moreover, the liturgical practice of the past was copied down and spread through staff notation. Previous notational styles assumed that the reader had an aural familiarity with the piece at hand, but Guido of Arezzo (ca. 991-d. after 1033) helped to create this new notation which specified the pitches of a melody precisely through a combination of the staff (a set of horizontal lines and spaces) with one or more clefs to identify the pitches C, F or (sometimes) G. Guido also developed a system for sightsinging that involved solmization, using pre-assigned syllables for particular pitches. Guido's system used hexachords, made up of six notes with only a half-step between the third and fourth and a whole-step elsewhere (ut--re--mi-fa--sol--la); to sing a melody with a larger range, one 'mutated' or shifted from one hexachord to another. The so-called Guidonian hand assigned each pitch and its hexachordal names to a knuckle of the hand, serving as a mnemonic device. Notes lying outside of the hand, including all accidentals except B-flat, were called musica ficta.
In addition to notational innovations, several new genres were established during this period of liturgical consolidation. The monophonic conductus, also known as the versus, follows a strophic structure, in which the music is repeated for each successive stanza of poetry. These pieces are thought to have served as accompaniment to liturgical action, as the celebrant moved from one location to another within the church or chapel. The trope, on the other hand, adds new textual and musical material to a pre- existent liturgical composition, particularly introits (the introductory chant for the mass) and the shorter chants of the ordinary. The trope members can come before, in the middle of, or after the host chant; they comment on and amplify the meaning of the original. The trope members were sung by soloists, even if the host chant was choral. Some tropes, such as the Easter and Christmas trope Quem quaeritis, include dialogue and short dramatic interludes, and are thought to be the forbearers to liturgical drama, which also evolved in this period.
Another new genre is the sequence, a separate choral composition which follows the Alleluia in the mass. Notker Balbulus (ca. 840-912) claimed to have invented the sequence by putting words to long untexted melismas as a memory aid; while this claim is probably exaggerated, the sequence as a genre is syllabic and has irregular phrase lengths which might reflect musical (rather than textual) inspiration. In the sequence, each musical line usually has one to four clauses, and the entire musical line is commonly repeated before moving to new musical material, giving a structure of A B B C C D D.... Most sequences were banned by the Council of Trent (1545-1563), and only five sequences remain in the modern chant repertory.
Finally, the earliest instructions for performing polyphony date to around 900 A.D. Alongside their discussion of melodic organization of a single voice, the Musica enchiriadis and Scholica enchiriadis give instructions for performing parallel organum, in which a given melody (the vox principalis) is harmonized by a second voice (the vox organalis) at a set interval below. When the first voice goes up and down, so does the second. A slightly more independent sound can be created by starting both parts on the same pitch and having one voice held steady (known as oblique motion) until the appropriate perfect interval (usually a fourth or fifth) is reached, and then commencing the parallel motion. This practice is simple enough to be improvised, though organum was presumably performed by soloists, rather than a full choir.
Perhaps the most famous composer of this period of liturgical additions was the twelfth-century mystic, abbess, author, and composer Hildegard von Bingen (1098-1179). She wrote antiphons (loosely poetic texts accompanied by exuberant, rhapsodic melodies) and sequences, though the repetitive structures of Notker's sequences can be hard to discern amidst the ornamentation of her associative melodic lines, and some sequences lack Notker's couplet structure altogether. She also wrote an early morality play known as the Ordo virtutum intended for her nuns at Rupertsberg. Hildegard's musical languages falls outside of the traditional modal practice of her day, which some have attributed to her lack of traditional musical training, but her literary efforts were sanctioned by the Pope, and the care with which her manuscripts were created reflects the respect she had within her community.
Early Polyphony: Organum, Conductus, Motet, ca. 1000-ca. 1300
The use of polyphony to ornament solo chants on special feast days evidently appealed to the medieval ear, for a version of composed polyphonic writing arose during the eleventh century. Curiously, the composed varieties of organum placed the original chant line on the bottom, and composed an organal part above the pre-existent melody. In the new note-against-note (or punctus contra punctum, i.e. contrapuntal) style of organum, each note of the original was still matched by a single note of the organal voice, but now each voice could move independently in pitch and direction. Thus, contrary motion supplemented parallel and oblique motion, though dissonances had to be avoided or resolved with care.
Even more elaborate was the so-called florid organum (also known as 'Aquitanian organum' or 'melismatic organum') which developed in south-west France during the early twelfth century. In this style, the organal voice now had several notes for each note of the principal voice. The effect was rhapsodic, but required close coordination between the two soloists, since the rhythm was not notated, and the bottom voice had to follow along carefully to know when to switch to the next pitch.
Thus, Notre Dame organum, which employs a rhythmic notation, seems to modern ears much more evolved than its stylistic predecessors. Notre Dame organum employs three distinctive rhythmic styles: organum purum in which both the upper voice and the lower voice move freely without a specified rhythm, copula in which the upper part moves in a strict rhythm while the bottom voice moves freely, and discant in which both parts move in strict rhythm. In all three styles, the lower voice, known as the tenor (from tenere, to hold), tends to move more slowly than the top voice; in organum purum or copula, the top voice can have thirty or more notes for each note of the tenor. The notation for the rhythmic sections is based on a group of patterns known as rhythmic modes; once a pattern is selected (e.g. short-long, short-long, short-long), it continues until a new pattern is adopted. The theorist Anonymous IV (named for its order among the anonymous treatises contained in Coussemaker's nineteenth-century Scriptorum de musica medii aevi, 1864-1876) discusses six rhythmic modes, and describes the effect that composers were able to achieve with them. According to his description, Leonin (fl. ca. 1163-90) was an excellent composer of organum who wrote a cycle of organa for the major feasts of the church year, a collection known as the Magnus liber organi. His successor Perotin (fl. ca. 1200), however, was better at composing discant, and also wrote for more than two voices. Perotin's compositions, and those of his anonymous contemporaries, offered alternative passages in a different style in a sort of a 'mix and match' rendition of the liturgical chant which served as the basis for the whole work. Thus, their efforts are known as substitute clausula. A piece of organum, then, would frequently include a mixture of different styles. Moreover, since only the solo sections were set polyphonically, the organum would also contrast with passages of the original plainchant sung by the choir in its original monophonic style.