The Introit Gaudeamus omnes, scripted in square notation in the 14th—15th century Graduale Aboense, honors Henry, patron saint of Finland.
Although the modern major and minor scales are strongly related to two of the church modes, the modern eight-tone scale is based on different harmonic principles and is organized differently from the scales of the church modes, which are based on six-note patterns called hexachords. The main notes in a hexachord are the dominant and the final. Depending on where the final falls in the sequence of the hexachord, the mode is characterized as either authentic or plagal. Modes with the same final share certain characteristics, and it is easy to modulate back and forth between them, hence the eight modes fall into four larger groupings based on their finals.
The New Testament mentions singing hymns during the Last Supper: "When they had sung the hymn, they went out to the Mount of Olives" . Other ancient witnesses such as Pope Clement I, Tertullian, St. Athanasius, and Egeria confirm the practice, although in poetic or obscure ways that shed little light on how music sounded during this period. The 3rd-century Greek "Oxyrhynchus hymn" survived with musical notation, but the connection between this hymn and the plainchant tradition is uncertain.
Musical elements that would later be used in the Roman Rite began to appear in the 3rd century. The Apostolic Tradition, attributed to the theologian Hippolytus, attests the singing of Hallel psalms with Alleluia as the refrain in early Christian agape feasts. Chants of the Office, sung during the canonical hours, have their roots in the early 4th century, when desert monks following St. Anthony introduced the practice of continuous psalmody, singing the complete cycle of 150 psalms each week. Around 375, antiphonal psalmody became popular in the Christian East; in 386, St. Ambrose introduced this practice to the West.
Scholars are still debating how plainchant developed during the 5th through the 9th centuries, as information from this period is scarce. Around 410, St. Augustine described the responsorial singing of a Gradual psalm at Mass. At ca. 520, Benedictus of Nursia established what is called the rule of St. Benedict, in which the protocol of the Divine Office for monastic use was laid down. Around 678, Roman chant was taught at York. Distinctive regional traditions of Western plainchant arose during this period, notably in the British Isles (Celtic chant), Spain (Mozarabic), Gaul (Gallican), and Italy (Old Roman, Ambrosian and Beneventan). These traditions may have evolved from a hypothetical year-round repertory of 5th-century plainchant after the western Roman Empire collapsed.
Scholars debate whether the essentials of the melodies originated in Rome, before the 7th century, or in Francia, in the 8th and early 9th centuries. Traditionalists point to evidence supporting an important role for Pope Gregory the Great between 590 and 604, such as that presented in H. Bewerung's article in the Catholic Encyclopedia. Scholarly consensus, supported by Willi Apel and Robert Snow, asserts instead that Gregorian chant developed around 750 from a synthesis of Roman and Gallican chant commissioned by Carolingian rulers in France. During a visit to Gaul in 752–753, Pope Stephen II had celebrated Mass using Roman chant. According to Charlemagne, his father Pepin abolished the local Gallican rites in favor of the Roman use, in order to strengthen ties with Rome. In 785–786, at Charlemagne's request, Pope Hadrian I sent a papal sacramentary with Roman chants to the Carolingian court. This Roman chant was subsequently modified, influenced by local styles and Gallican chant, and later adapted into the system of eight modes. This Frankish-Roman Carolingian chant, augmented with new chants to complete the liturgical year, became known as "Gregorian." Originally the chant was probably so named to honor the contemporary Pope Gregory II, but later lore attributed the authorship of chant to his more famous predecessor Gregory the Great. Gregory was portrayed dictating plainchant inspired by a dove representing the Holy Spirit, giving Gregorian chant the stamp of holy authority. Gregory's authorship is popularly accepted as fact to this day.
The other plainchant repertories of the Christian West faced severe competition from the new Gregorian chant. Charlemagne continued his father's policy of favoring the Roman Rite over the local Gallican traditions. By the 9th century the Gallican rite and chant had effectively been eliminated, although not without local resistance. The Gregorian chant of the Sarum Rite displaced Celtic chant. Gregorian coexisted with Beneventan chant for over a century before Beneventan chant was abolished by papal decree (1058). Mozarabic chant survived the influx of the Visigoths and Moors, but not the Roman-backed prelates newly installed in Spain during the Reconquista. Restricted to a handful of dedicated chapels, modern Mozarabic chant is highly Gregorianized and bears no musical resemblance to its original form. Ambrosian chant alone survived to the present day, preserved in Milan due to the musical reputation and ecclesiastical authority of St. Ambrose.
Gregorian chant eventually replaced the local chant tradition of Rome itself, which is now known as Old Roman chant. In the 10th century, virtually no musical manuscripts were being notated in Italy. Instead, Roman Popes imported Gregorian chant from the German Holy Roman Emperors during the 10th and 11th centuries. For example, the Credo was added to the Roman Rite at the behest of the German emperor Henry II in 1014. Reinforced by the legend of Pope Gregory, Gregorian chant was taken to be the authentic, original chant of Rome, a misconception that continues to this day. By the 12th and 13th centuries, Gregorian chant had supplanted or marginalized all the other Western plainchant traditions.
Later sources of these other chant traditions show an increasing Gregorian influence, such as occasional efforts to categorize their chants into the Gregorian modes. Similarly, the Gregorian repertory incorporated elements of these lost plainchant traditions, which can be identified by careful stylistic and historical analysis. For example, the Improperia of Good Friday are believed to be a remnant of the Gallican repertory.
Gregorian chant has in its long history been subjected to a series of redactions to bring it up to changing contemporary tastes and practice. The more recent redaction undertaken in the Benedictine Abbey of St. Pierre, Solesmes, has turned into a huge undertaking to restore the allegedly corrupted chant to a hypothetical "original" state. Early Gregorian chant was revised to conform to the theoretical structure of the modes. In 1562–63, the Council of Trent banned most sequences. Guidette's Directorium chori, published in 1582, and the Editio medicea, published in 1614, drastically revised what was perceived as corrupt and flawed "barbarism" by making the chants conform to contemporary aesthetic standards. In 1811, the French musicologist Alexandre-Étienne Choron, as part of a conservative backlash following the liberal Catholic orders' inefficacy during the French Revolution, called for returning to the "purer" Gregorian chant of Rome over French corruptions.
In the late 19th century, early liturgical and musical manuscripts were unearthed and edited. Earlier, Dom Prosper Gueranger revived the monastic tradition in Solesmes. Re-establishing the Divine Office was among his priorities, but no proper chantbooks existed. Many monks were sent out to libraries throughout Europe to find relevant Chant manuscripts. In 1871, however, the old Medicea edition was reprinted (Pustet, Regensburg) which Pope Pius IX declared the only official version. In their firm belief that they were on the right way, Solesmes increased its efforts. In 1889, after decades of research, the monks of Solesmes released the first book in a planned series, the Paléographie Musicale. The incentive of its publication was to demonstrate the corruption of the 'Medicea' by presenting photographed notations originating from a great variety of manuscripts of one single chant, which Solesmes called forth as witnesses to assert their own reforms. The monks of Solesmes brought in their heaviest artillery in this battle, as indeed the academically sound 'Paleo' was intended to be a war-tank, meant to abolish once and for all the corrupted Pustet edition. On the evidence of congruence throughout various manuscripts (which were duely published in facsimile editions with ample editorial introductions) Solesmes was able to work out a practical reconstruction. This reconstructed chant was academically praised, but rejected by Rome until 1903, when Pope Leo XIII died. His successor, Pope Pius X, promptly accepted the Solesmes chant — now compiled as the Liber usualis — as authoritative. In 1904, the Vatican edition of the Solesmes chant was commissioned. Serious academic debates arose, primarily owing to stylistic liberties taken by the Solesmes editors to impose their controversial interpretation of rhythm. The Solesmes editions insert phrasing marks and note-lengthening episema and mora marks not found in the original sources. Conversely, they omit significative letters found in the original sources, which give instructions for rhythm and articulation such as speeding up or slowing down. These editorial practices has placed the historical authenticity of the Solesmes interpretation in doubt. Ever since the restoration of Chant was taken up in Solesmes, there have been lengthy discussions of exactly what course was to be taken. Some favored a strict academic rigour and wanted to postpone publications, while others concentrated on practical matters and wanted to supplant the corrupted tradition as soon as possible. Roughly a century later, this breach between a strict musicological approach and the interest of the Church which is in keeping one central tradition for the congregation without too much confusing changes made to the repertory. Thus the established performance tradition since the onset of the restoration is at odds with musicological evidence.
In his motu proprio Tra le sollicitudine, Pius X mandated the use of Gregorian chant, encouraging the faithful to sing the Ordinary of the Mass, although he reserved the singing of the Propers for males. While this custom is maintained in traditionalist Catholic communities, the Catholic Church no longer persists with this ban. Vatican II officially allowed worshipers to substitute other music, particularly modern music in the vernacular, in place of Gregorian chant, although it did reaffirm that Gregorian chant was still the official music of the Catholic Church, and the music most suitable for worship.
Gregorian chants fall into two broad categories of melody: recitatives and free melodies. The simplest kind of melody is the liturgical recitative. Recitative melodies are dominated by a single pitch, called the reciting tone. Other pitches appear in melodic formulae for incipits, partial cadences, and full cadences. These chants are primarily syllabic. For example, the Collect for Easter consists of 127 syllables sung to 131 pitches, with 108 of these pitches being the reciting note A and the other 23 pitches flexing down to G. Liturgical recitatives are commonly found in the accentus chants of the liturgy, such as the intonations of the Collect, Epistle, and Gospel during the Mass, and in the direct psalmody of the Office.
Psalmodic chants, which intone psalms, include both recitatives and free melodies. Psalmodic chants include direct psalmody , antiphonal chants, and responsorial chants. In direct psalmody, psalm verses are sung without refrains to simple, formulaic tones. Most psalmodic chants are antiphonal and responsorial, sung to free melodies of varying complexity.
Antiphonal chants such as the Introit, and Communion originally referred to chants in which two choirs sang in alternation, one choir singing verses of a psalm, the other singing a refrain called an antiphon. Over time, the verses were reduced in number, usually to just one psalm verse and the Doxology, or even omitted entirely. Antiphonal chants reflect their ancient origins as elaborate recitatives through the reciting tones in their melodies. Ordinary chants, such as the Kyrie and Gloria, are not considered antiphonal chants, although they are often performed in antiphonal style.
Responsorial chants such as the Gradual, Alleluia, Offertory, and the Office Responsories originally consisted of a refrain called a respond sung by a choir, alternating with psalm verses sung by a soloist. Responsorial chants are often composed of an amalgamation of various stock musical phrases, pieced together in a practice called centonization. Tracts are melismatic settings of psalm verses and use frequent recurring cadences and they are strongly centonized.
Gregorian chant evolved to fulfill various functions in the Roman Catholic liturgy. Broadly speaking, liturgical recitatives are used for texts intoned by deacons or priests. Antiphonal chants accompany liturgical actions: the entrance of the officiant, the collection of offerings, and the distribution of sanctified bread and wine. Responsorial chants expand on readings and lessons.
The non-psalmodic chants, including the Ordinary of the Mass, sequences, and hymns, were originally intended for congregational singing. The structure of their texts largely defines their musical style. In sequences, the same melodic phrase is repeated in each couplet. The strophic texts of hymns use the same syllabic melody for each stanza.
Around 1025, Guido d'Arezzo revolutionized Western music with the development of the gamut, in which pitches in the singing range were organized into overlapping hexachords. Hexachords could be built on C (the natural hexachord, C-D-E^F-G-A), F (the soft hexachord, using a B-flat, F-G-A^Bb-C-D), or G (the hard hexachord, using a B-natural, G-A-B^C-D-E). The B-flat was an integral part of the system of hexachords rather than an accidental. The use of notes outside of this collection was described as musica ficta.
Gregorian chant was categorized into eight modes, influenced by the eightfold division of Byzantine chants called the oktoechos. Each mode is distinguished by its final, dominant, and ambitus. The final is the ending note, which is usually an important note in the overall structure of the melody. The dominant is a secondary pitch that usually serves as a reciting tone in the melody. Ambitus refers to the range of pitches used in the melody. Melodies whose final is in the middle of the ambitus, or which have only a limited ambitus, are categorized as plagal, while melodies whose final is in the lower end of the ambitus and have a range of over five or six notes are categorized as authentic. Although corresponding plagal and authentic modes have the same final, they have different dominants. The existent pseudo-Greek names of the modes, rarely used in medieval times, derive from a misunderstanding of the Ancient Greek modes; the prefix "Hypo-" (under, Gr.) indicates a plagal mode, where the melody moves below the final. In contemporary Latin manuscripts the modes are simply called Protus authentus /plagalis, Deuterus, Tritus and Tetrardus: the 1st mode, authentic or plagal, the 2nd mode etc. In the Roman Chantbooks the modes are indicated by Roman numerals.
Although the modes with melodies ending on A, B, and C are sometimes referred to as Aeolian, Locrian, and Ionian, these are not considered distinct modes and are treated as transpositions of whichever mode uses the same set of hexachords. The actual pitch of the Gregorian chant is not fixed, so the piece can be sung in whichever range is most comfortable.
Certain classes of Gregorian chant have a separate musical formula for each mode, allowing one section of the chant to transition smoothly into the next section, such as the psalm tones between antiphons and psalm verses.
Not every Gregorian chant fits neatly into Guido's hexachords or into the system of eight modes. For example, there are chants—especially from German sources—whose neumes suggest a warbling of pitches between the notes E and F, outside the hexachord system. Early Gregorian chant, like Ambrosian and Old Roman chant, whose melodies are most closely related to Gregorian, did not use the modal system. The great need for a system of organizing chants lies in the need to link antiphons with standard tones, as in for example, the psalmody at the Office. Using Psalm Tone i with an antiphon in Mode 1 makes for a smooth transition between the end of the antiphon and the intonation of the tone, and the ending of the tone can then be chosen to provide a smooth transition back to the antiphon. As the modal system gained acceptance, Gregorian chants were edited to conform to the modes, especially during 12th-century Cistercian reforms. Finals were altered, melodic ranges reduced, melismas trimmed, B-flats eliminated, and repeated words removed. Despite these attempts to impose modal consistency, some chants—notably Communions—defy simple modal assignment. For example, in four medieval manuscripts, the Communion Circuibo was transcribed using a different mode in each.
Chants sometimes fall into melodically related groups. The musical phrases centonized to create Graduals and Tracts follow a musical "grammar" of sorts. Certain phrases are used only at the beginnings of chants, or only at the end, or only in certain combinations, creating musical families of chants such as the Iustus ut palma family of Graduals. Several Introits in mode 3, including Loquetur Dominus above, exhibit melodic similarities. Mode III (E authentic) chants have C as a dominant, so C is the expected reciting tone. These mode III Introits, however, use both G and C as reciting tones, and often begin with a decorated leap from G to C to establish this tonality. Similar examples exist throughout the repertory.
The earliest notated sources of Gregorian chant (written ca. 950) used symbols called neumes (Gr. sign (of the hand) to indicate tone-movements and relative duration within each syllable. A sort of musical stenography that seems to focus on gestures and tone-movements but not the specific pitches of individual notes, nor the relative starting pitches of each neume. Given the fact that Chant was learned in an oral tradition in which the texts and melodies were sung from memory, this was obviously not necessary. The neumatic manuscripts display great sophistication and precision in notation and a wealth of graphic signs to indicate the musical gesture and proper pronunciation of the text. Scholars postulate that this practice may have been derived from cheironomic hand-gestures, the ekphonetic notation of Byzantine chant, punctuation marks, or diacritical accents. Later adaptations and innovations included the use of a dry-scratched line or an inked line or two lines, marked C or F showing the relative pitches between neumes. Consistent relative heightening first developed in the Aquitaine region, particularly at St. Martial de Limoges, in the first half of the eleventh century. Many German-speaking areas, however, continued to use unpitched neumes into the twelfth century. Additional symbols developed, such as the custos, placed at the end of a system to show the next pitch. Other symbols indicated changes in articulation, duration, or tempo, such as a letter "t" to indicate a tenuto. Another form of early notation used a system of letters corresponding to different pitches, much as Shaker music is notated.
By the 13th century, the neumes of Gregorian chant were usually written in square notation on a four-line staff with a clef, as in the Graduale Aboense pictured above. In square notation, small groups of ascending notes on a syllable are shown as stacked squares, read from bottom to top, while descending notes are written with diamonds read from left to right. When a syllable has a large number of notes, a series of smaller such groups of neumes are written in succession, read from left to right. The oriscus, quilisma, and liquescent neumes indicate special vocal treatments, that have been largely neglected due to uncertainty as to how to sing them. Since the 1970s, with the influential insights of Dom. E. Cardine (see below under 'rhythm'), ornamental neumes have received more attention from both researchers and performers. B-flat is indicated by a "b-mollum" (Lat. soft), a rounded undercaste 'b' placed to the left of the entire neume in which the note occurs, as shown in the "Kyrie" to the right. When necessary, a "b-durum" (Lat. hard), written squarely, indicates B-natural and serves to cancel the b-mollum . This system of square notation is standard in modern chantbooks.
Chant was normally sung in unison. Later innovations included tropes, which is a new text sung to the same melodic phrases in a melismatic chant (repeating an entire Alleluia-melody on a new text for instance, or repeating a full phrase with a new text that comments on the previously sung text) and various forms of organum, (improvised) harmonic embellishment of chant melodies focusing on octaves, fifths, fourths, and, later, thirds. Neither tropes nor organum, however, belong to the chant repertory proper. The main exception to this is the sequence, whose origins lay in troping the extended melisma of Alleluia chants known as the jubilus, but the sequences, like the tropes, were later officially suppressed. The Council of Trent struck sequences from the Gregorian corpus, except those for Easter, Pentecost, Corpus Christi and All Souls' Day.
We do not know much about the particular vocal stylings or performance practices used for Gregorian chant in the Middle Ages. On occasion, the clergy was urged to have their singers perform with more restraint and piety. This suggests that virtuosic performances occurred, contrary to the modern stereotype of Gregorian chant as slow-moving mood music. This tension between musicality and piety goes far back; Gregory the Great himself criticized the practice of promoting clerics based on their charming singing rather than their preaching. However, Odo of Cluny, a renowned monastic reformer, praised the intellectual and musical virtuosity to be found in chant:
For in these [Offertories and Communions] there are the most varied kinds of ascent, descent, repeat..., delight for the cognoscenti, difficulty for the beginners, and an admirable organization... that widely differs from other chants; they are not so much made according to the rules of music... but rather evince the authority and validity... of music.
True antiphonal performance by two alternating choruses still occurs, as in certain German monasteries. However, antiphonal chants are generally performed in responsorial style by a solo cantor alternating with a chorus. This practice appears to have begun in the Middle Ages. Another medieval innovation had the solo cantor sing the opening words of responsorial chants, with the full chorus finishing the end of the opening phrase. This innovation allowed the soloist to fix the pitch of the chant for the chorus and to cue the choral entrance.
One school of thought, including Wagner, Jammers, and Lipphardt, advocated imposing rhythmic meters on chants, although they disagreed on how that should be done. An opposing interpretation, represented by Pothier and Mocquereau, supported a free rhythm of equal note values, although some notes are lengthened for textual emphasis or musical effect. The modern Solesmes editions of Gregorian chant follow this interpretation. Mocquereau divided melodies into two- and three-note phrases, each beginning with an ictus, akin to a beat, notated in chantbooks as a small vertical mark. These basic melodic units combined into larger phrases through a complex system expressed by cheironomic hand-gestures. This approach prevailed during the twentieth century, propagated by Justine Ward's program of music education for children, until the liturgical role of chant was diminished after the liturgical reforms of Paul VI, and new scholarship "essentially discredited" Mocquereau's rhythmic theories.
Common modern practice favors performing Gregorian chant with no beat or regular metric accent, largely for aesthetic reasons. The text determines the accent while the melodic contour determines the phrasing. The note lengthenings recommended by the Solesmes school remain influential, though not prescriptive.
Dom Eugene Cardine, (1905–1988) monk from Solesmes, published his 'Semiologie Gregorienne' in 1970 in which he clearly explains the musical significance of the neumes of the early chant manuscripts. Cardine shows the great diversity of neumes and graphic variations of the basic shape of a particular neume, which can not be expressed in the square notation. This variety in notation must have served a practical purpose and therefore a musical significance. Nine years later, the Graduale Triplex was published, in which the Roman Gradual, containing all the chants for Mass in a Year's cycle, appeared with the neumes of the two most important manuscripts copied under and over the 4-line staff of the square notation. The Graduale Triplex made widely accessible the original notation of Sankt Gallen and Laon (compiled after 930 AD) in a single chantbook and was a huge step forward. Dom Cardine had many students who have each in their own way continued their semiological studies, some of whom also started experimenting in applying the newly understood principles in performance practice. The studies of Cardine and his students (Godehard Joppich, Luigi Augustoni, Marie-Noël Colette, Rupert Fischer, Marie-Claire Billecocq to name a few) have clearly demonstrated that rhythm in Gregorian chant as notated in the 10th century rhythmic manuscripts (notably Skt. Gallen and Laon) manifest such rhythmic diversity and melodic–rhythmic ornamentations for which there is hardly a living performance tradition in the Western world. Contemporary groups that endeavour to sing according to the manuscript traditions have evolved after 1975. Some practising researchers favour a closer look at non Western (liturgical) traditions, in such cultures where the tradition of modal monophony was never abandoned.
Another group with different views are the mensuralists or the proportionalists, who maintain that rhythm has to be interpreted proportionately, where shorts are exactly half the longs. This view is advocated by John Blackley and his 'Schola Antiqua New York'.
Introits cover the procession of the officiants. Introits are antiphonal chants, typically consisting of an antiphon, a psalm verse, a repeat of the antiphon, an intonation of the Gloria Patri Doxology, and a final repeat of the antiphon. Reciting tones often dominate their melodic structures.
Graduals are responsorial chants that follow the reading of the Epistle. Graduals usually result from centonization; stock musical phrases are assembled like a patchwork to create the full melody of the chant, creating families of musically related melodies. Graduals are accompanied by a elaborate Verse, so that it actually consists in two different parts, A B. Often the first part is sung again, creating a 'rondeau' A B A. At least the verse, if not the complete gradual, is for the solo cantor and are in elaborate, ornate style with long, wide-ranged melisma's.
The Alleluia is known for the jubilus, an extended joyful melisma on the last vowel of 'Alleluia'. The Alleluia is also in two parts, the alleluia proper and the psalmverse, by which the Alleluia is identified (Alleluia V. Pascha nostrum) . The last melism of the verse is the same as the jubilus attached to the Alleluia. Alleluias are not sung during penitential times, such as Lent. Instead, a Tract is chanted, usually with texts from the Psalms. Tracts, like Graduals, are highly centonized.
Sequences are sung poems based on couplets. Although many sequences are not part of the liturgy and thus not part of the Gregorian repertory proper, Gregorian sequences include such well-known chants as Victimae paschali laudes and Veni Sancte Spiritus. According to Notker Balbulus, an early sequence writer, their origins lie in the addition of words to the long melismas of the jubilus of Alleluia chants.
Offertories are sung during the offering of Eucharistic bread and wine. Offertories once had highly prolix melodies in their verses, but the use of verses in Gregorian Offertories disappeared around the 12th century. These verses however, are among the most ornate and elaborated in the whole chant repertoir. Offertories are in form closest to Responsories, which are likewise accompanied by at least one Verse and the opening sections of both Off. and Resp. are partly repeated after the verse(s). This last section is therefore called the 'repetenda' and is in performance the last melodic line of the chant.
Communions are sung during the distribution of the Eucharist. In presentation the Communio is similar to the Introitus, an antiphon with a series of psalm verses. Communion melodies are often tonally ambiguous and do not fit into a single musical mode which has led to the same communio being classed in different modes in different manuscripts or editions.
The Kyrie consists of a threefold repetition of "Kyrie eleison" ("Lord, have mercy"), a threefold repetition of "Christe eleison" ("Christ have mercy"), followed by another threefold repetition of "Kyrie eleison." In older chants, "Kyrie eleison imas" ("Lord, have mercy on us") can be found. The Kyrie is distinguished by its use of the Greek language instead of Latin. Because of the textual repetition, various musical repeat structures occur in these chants. The following, Kyrie ad. lib. VI as transmitted in a Cambrai manuscript, uses the form ABA CDC EFE', with shifts in tessitura between sections. The E' section, on the final "Kyrie eleison," itself has an aa'b structure, contributing to the sense of climax.
The Gloria recites the Greater Doxology, and the Credo intones the Nicene Creed. Because of the length of these texts, these chants often break into musical subsections corresponding with textual breaks. Because the Credo was the last Ordinary chant to be added to the Mass, there are relatively few Credo melodies in the Gregorian corpus.
Technically, the Ite missa est and the Benedicamus Domino, which conclude the Mass, belong to the Ordinary. They have their own Gregorian melodies, but because they are short and simple, and have rarely been the subject of later musical composition, they are often omitted in discussion.
At the close of the Office, one of four Marian antiphons is sung. These songs, Alma Redemptoris Mater (see top of article), Ave Regina caelorum, Regina caeli laetare, and Salve, Regina, are relatively late chants, dating to the 11th century, and considerably more complex than most Office antiphons. Apel has described these four songs as "among the most beautiful creations of the late Middle Ages.
Gregorian melodies provided musical material and served as models for tropes and liturgical dramas. Vernacular hymns such as "Christ ist erstanden" and "Nun bitten wir den heiligen Geist" adapted original Gregorian melodies to translated texts. Secular tunes such as the popular Renaissance "In Nomine" were based on Gregorian melodies. Beginning with the improvised harmonizations of Gregorian chant known as organum, Gregorian chants became a driving force in medieval and Renaissance polyphony. Often, a Gregorian chant (sometimes in modified form) would be used as a cantus firmus, so that the consecutive notes of the chant determined the harmonic progression. The Marian antiphons, especially Alma Redemptoris Mater, were frequently arranged by Renaissance composers. The use of chant as a cantus firmus was the predominant practice until the Baroque period, when the stronger harmonic progressions made possible by an independent bass line became standard.
The Catholic Church later allowed polyphonic arrangements to replace the Gregorian chant of the Ordinary of the Mass. This is why the Mass as a compositional form, as set by composers like Palestrina or Mozart, features a Kyrie but not an Introit. The Propers may also be replaced by choral settings on certain solemn occasions. Among the composers who most frequently wrote polyphonic settings of the Propers were William Byrd and Tomás Luis de Victoria. These polyphonic arrangements usually incorporate elements of the original chant.
Gregorian chant as plainchant experienced a popular resurgence during the New Age music and world music movements of the 1980s and '90s. The iconic album was Chant, recorded by the Benedictine monks of Santo Domingo de Silos, which was marketed as music to inspire timeless calm and serenity. In 2008, the Cistercian Monks of Austrian Heiligenkreuz Abbey released the CD Chant–Music for Paradise, which became the best-selling album of the Austrian pop charts and peaked #7 of the UK charts. In the USA, the album was released under the title Chant–Music for the Soul and peaked #187. It became conventional wisdom that listening to Gregorian chant increased the production of beta waves in the brain, reinforcing the popular reputation of Gregorian chant as tranquilizing music. Gregorian chant has often been parodied for its supposed monotony, both before and after the release of Chant. Famous references include the flagellant monks in Monty Python and the Holy Grail intoning "Pie Jesu Domine." The asteroid 100019 Gregorianik is named in its honour, using the German short form of the term. Gregorian chanting has been also used in Vision of Escaflowne anime series.