For centuries, Christians entering a Roman Catholic Mass have encountered something unusual almost immediately. Surrounded by a liturgy historically associated with Latin, they hear a prayer that remained stubbornly Greek.
Kyrie eleison.
Lord, have mercy.
Christe eleison.
Christ, have mercy.
The words are short enough to be spoken in a breath, yet their history reaches from the Greek-speaking world of antiquity into the worship of modern churches. They appear in forms of Eastern Christianity, in the Roman Mass, in Lutheran worship, in medieval chant manuscripts, in Renaissance polyphony, and in countless musical settings written long after Greek had ceased to be the everyday language of Western Christianity.
The survival of the phrase has sometimes encouraged claims that the Kyrie must be one of the oldest unchanged parts of Christian worship. Its history is more complicated. The words themselves are ancient, and their biblical roots are unmistakable, but the evidence for Kyrie eleison as a formal congregational liturgical response becomes secure only in the fourth century. From there, the documentary trail becomes remarkably rich.
Travelers heard it in Jerusalem. Church orders preserved it in Eastern litanies. Bishops in sixth-century Gaul ordered their congregations to adopt it. Benedict placed it within monastic prayer. Gregory the Great explained how Roman Christians used it differently from Greek Christians. Medieval singers eventually transformed the simple response into some of the most elaborate music of the Mass.
The history of the Kyrie is therefore not simply the history of two Greek words. It is a history of how Christian worship traveled from language to language and region to region while preserving a prayer simple enough to survive nearly every change around it.
Before the Kyrie Became a Liturgical Prayer
The language behind Kyrie eleison existed before Christians made it part of their worship.
The Greek word kyrios means lord or master, while eleison is an imperative form connected with mercy or compassion. Together, the expression is a direct appeal: Lord, have mercy.
The language of calling upon the Lord for mercy had deep roots in the Greek Scriptures. The Septuagint, the ancient Greek translation of the Hebrew Scriptures widely used among Greek-speaking Jews and early Christians, repeatedly joins appeals to the Lord with requests for mercy. These passages did not yet constitute the later Christian Kyrie of the Mass, but they created the scriptural vocabulary from which such prayer naturally developed.
The connection becomes even clearer in the New Testament.
The Gospels repeatedly describe people approaching Jesus with pleas for mercy. Blind men, lepers, parents seeking healing for their children, and others in distress cry out for divine compassion. Matthew 20:30 is particularly striking. Two blind men hear that Jesus is passing and cry out with words that include Kyrie, eleison hemas, or “Lord, have mercy on us.”
For later Christians who knew the Gospels in Greek, the Kyrie therefore sounded like the language of people encountering Christ directly. It was not an abstract theological formula. It was the cry of someone who needed help.
There is also evidence that the wording itself was not exclusively Christian. In the second century, the philosopher Epictetus used the expression kyrie, eleison while describing someone anxiously appealing for divine help. His use should not be treated as proof that Christians borrowed their prayer from pagan religion. It demonstrates something more basic and historically useful: the combination of these words could function naturally as a Greek appeal for mercy before it became one of Christianity’s most recognizable liturgical formulas.
Christianity took language that Greek speakers could understand and gave it a particular biblical and Christ-centered life.
The Kyrie in the Fourth-Century Church
The historical picture becomes much clearer during the fourth century.
One of the most important witnesses is Book VIII of the Apostolic Constitutions, a collection generally associated with the late-fourth-century Christian East and particularly with the Syrian or Antiochene environment. Its descriptions of worship include lengthy prayers led by a deacon in which the congregation repeatedly responds by asking the Lord for mercy.
The pattern is important. The Kyrie was not originally simply an isolated chant inserted between two other parts of the Mass. It functioned as the people’s response to petitions.
The deacon might call the congregation to pray for catechumens, penitents, the sick, travelers, bishops, clergy, married Christians, children, prisoners, enemies, or the Church throughout the world. The faithful answered with an appeal to divine mercy. At one point, the text instructs that when individuals are named, the people are to respond, “Lord, have mercy,” with the children responding first.
The structure resembles a conversation between minister and congregation. One voice announces the need. Many voices answer.
That form remains familiar in Eastern Christian litanies today, where repeated appeals of Kyrie eleison continue to accompany petitions for the Church, the world, particular people, and particular needs.
The Apostolic Constitutions provide strong documentary evidence, but another fourth-century witness allows us to move from a written church order into an actual congregation.
Her name was Egeria.
Egeria Hears “Kyrie Eleison” in Jerusalem
Sometime during the 380s, a Christian woman conventionally known as Egeria traveled through the biblical lands and recorded what she encountered. Her surviving travel narrative is one of the most valuable eyewitness accounts of Christian worship in late antiquity.
In Jerusalem, Egeria attended worship at the Anastasis, the complex associated with the tomb of Christ. She described evening services illuminated by lamps, with psalms, antiphons, clergy, worshippers, prayers, and processions filling the sacred spaces of the city.
Then she recorded a small detail that became enormously important for the history of Christian liturgy.
As a deacon commemorated individuals during prayer, children standing nearby responded again and again with Kyrie eleyson. Egeria explained the Greek expression for her Latin readers as miserere Domine, meaning “Lord, have mercy.” She even emphasized the overwhelming number of voices answering the petitions.
This is among the clearest early eyewitness descriptions of the Kyrie functioning as a congregational response.
Egeria’s explanation is also revealing. She evidently believed that her readers needed the Greek expression translated. That detail warns against assuming that every Western Christian already knew the Kyrie simply because the phrase was widespread in parts of the Christian East.
In Jerusalem, however, the prayer was alive.
Children knew it. Congregations repeated it. Deacons structured petitions around it.
By the end of the fourth century, Kyrie eleison had become part of the soundscape of Christian worship in one of Christianity’s most important cities.
From the Christian East Toward the Latin West
The movement of the Kyrie into Western worship was gradual.
Latin Christianity already possessed its own vocabulary of mercy. Domine, miserere and similar expressions could communicate the same basic petition. Yet the Greek words themselves eventually crossed linguistic boundaries.
One of the most important pieces of evidence comes not from Rome but from southern Gaul.
On November 5, 529, bishops gathered at the Second Council of Vaison under the leadership of Caesarius of Arles. Their surviving canons dealt with practical church life, preaching, worship, and the organization of local congregations.
Canon III turned directly to the Kyrie.
The bishops observed that a sweet and spiritually beneficial custom had already been introduced at the Apostolic See, throughout the Eastern provinces, and in Italy: Kyrie eleison was being said frequently and with deep devotion and compunction. They ordered the same custom introduced into their churches at Matins, Mass, and Vespers.
The importance of the canon is difficult to exaggerate.
Vaison gives a geographical snapshot of the Kyrie’s expansion. The bishops knew it as an established Eastern practice. They also associated it with Italy and the Apostolic See at Rome. Now they deliberately prescribed it for churches in their own region of Gaul.
The wording also suggests that they were not merely interested in adding two foreign words to a service. They valued the repetition itself. The Kyrie was supposed to be offered with feeling and compunction.
It was a prayer designed to be repeated because human beings never exhausted their need for mercy.
Benedict and the Kyrie of the Monastery
At approximately the same period, the Kyrie was finding another home in Western Christianity: the monastery.
The Rule of Saint Benedict, traditionally associated with Benedict of Nursia and the sixth century, repeatedly places Kyrie eleison within the daily cycle of monastic prayer.
Chapter 17 describes the arrangement of the daytime Hours. At Prime, after the psalms and a reading, came a versicle, the Kyrie, and the concluding prayers. Terce, Sext, and None followed a comparable structure, while Compline also included the Kyrie near its conclusion.
This matters because monasteries became some of the great engines of liturgical preservation and transmission in medieval Europe.
A phrase repeated every day does not remain merely a sentence in a book. It enters memory. Monks heard it at the Hours, learned its position within worship, transmitted it to new communities, and copied liturgical texts across generations.
By the sixth century, therefore, the Kyrie was no longer simply an Eastern response encountered by Western travelers. It was becoming embedded in Western religious life.
Yet Rome would give the prayer a form that distinguished it from the Eastern practice from which it had developed.
Gregory the Great Explains the Roman Kyrie
Around the end of the sixth century, Pope Gregory I left historians an unusually valuable explanation of Roman liturgical practice.
In Book IX, Letter 12 of his Registrum Epistolarum, Gregory responded to criticism that he had supposedly imitated the Church of Constantinople in several liturgical matters. Among the accusations was that he had caused the Kyrie to be used.
Gregory’s answer is crucial because he did not simply claim that Rome and the Greeks used the same practice.
He emphasized their differences.
Among the Greeks, Gregory explained, the Kyrie was said together. At Rome, clergy said it and the people responded. He then identified another distinctly Roman feature. Romans also said Christe eleison, “Christ, have mercy,” which Gregory stated the Greeks did not use in the same way. He added that during daily Masses certain other material could be omitted so that Kyrie eleison and Christe eleison could receive greater attention as words of supplication.
This letter makes it dangerous to repeat the old claim that Gregory simply invented the Kyrie or introduced it wholesale into Rome.
The development was more complicated.
The Kyrie had reached Western Christianity before Gregory. Vaison proves that in 529, decades before Gregory became pope, bishops in Gaul already associated the practice with Rome. Gregory’s testimony instead captures a stage when the Roman Church had adapted the Kyrie into its own liturgical pattern.
The Greek prayer had moved west, but it did not remain unchanged.
Rome made it Roman.
From Congregational Litany to Liturgical Chant
As the early medieval centuries passed, another transformation took place.
The Kyrie increasingly became associated with the singers responsible for the music of the Mass.
The early medieval Ordo Romanus I, one of the fundamental sources for understanding Roman ceremonial, describes the schola beginning the Kyrie after the entrance antiphon. Even more interestingly, the leader of the schola watches the pope for a signal indicating when the number of repetitions should change or conclude.
That detail reveals something important about the history of the familiar ninefold Kyrie.
The number of invocations was not always rigidly fixed.
Later Western practice became famous for a pattern of three invocations of Kyrie eleison, three of Christe eleison, and three more of Kyrie eleison. Medieval commentators eventually found Trinitarian symbolism in this arrangement, connecting groups of three with Father, Son, and Holy Spirit.
Such interpretations became spiritually meaningful, but they should not simply be projected backward into the fourth century. The earliest evidence presents the Kyrie primarily as a repeated response to petitions rather than as a deliberately constructed ninefold Trinitarian formula.
The changing role of the schola also opened the door to a musical transformation.
Two Greek words that could be spoken almost instantly became capable of lasting far longer when sung.
The Medieval Kyrie Becomes Music
The Kyrie became one of the great musical canvases of medieval Christianity.
Because the text was so short, composers and singers could stretch its syllables across elaborate sequences of notes. Melodies developed, circulated, changed, and became associated with particular liturgical settings.
Eventually medieval musicians also added words to existing melodic passages, producing Kyrie tropes. Instead of singing only the ancient Greek invocation, singers could insert additional devotional or theological language around it.
Manuscripts preserve Kyries known by names such as Kyrie fons bonitatis, Cunctipotens genitor Deus, and Orbis factor. These titles represent a world in which the once-simple congregational response had become part of a sophisticated musical and textual culture.
The development did not erase the original words. Quite the opposite. The words became the framework around which elaboration occurred.
Medieval commentators also tried to explain why a predominantly Latin Church continued singing Greek. For them, the linguistic survival of the Kyrie itself demanded interpretation. Greek, Latin, Hebrew expressions, biblical language, theological symbolism, and inherited tradition all existed side by side within medieval worship.
By this point, the Kyrie had traveled a remarkable distance from the congregational response described by Egeria in Jerusalem.
Yet the essential appeal remained recognizable.
Lord, have mercy.
The Reformation Could Not Easily Remove It
The Protestant Reformation dismantled, translated, challenged, or reorganized many elements of medieval Western worship.
The Kyrie survived.
Martin Luther provides one of the clearest examples. In his 1523 Formula missae, Luther retained much of the inherited structure of the Western Mass while removing or reinterpreting elements he believed conflicted with his theology. He specifically defended the Kyrie as an ancient and unobjectionable part of Christian worship. Modern scholarship on Luther’s liturgical reforms notes that he preserved the Kyrie along with other ancient portions of the Mass Ordinary.
Three years later, his Deutsche Messe placed a threefold Kyrie eleison near the beginning of worship.
Its survival in Lutheran worship demonstrates the unusual strength of the prayer.
Debates could rage over sacrifice, priesthood, saints, images, ecclesiastical authority, language, and the Eucharist, yet Christians divided by those controversies could still pray for mercy in words inherited from the ancient Church.
The Kyrie had become older than many of the institutions fighting over its meaning.
The Kyrie in the Modern Roman Mass
The Roman Catholic liturgy continued to preserve the Kyrie through later centuries, including the liturgical standardization associated with the period after the Council of Trent.
In the older Roman form, worshippers became familiar with the ninefold arrangement of three Kyrie eleison, three Christe eleison, and three Kyrie eleison invocations.
Twentieth-century liturgical reform changed the ordinary pattern.
The current General Instruction of the Roman Missal places the Kyrie after the Penitential Act unless it has already formed part of that act. It describes the Kyrie as a chant through which the faithful acclaim the Lord and implore his mercy. Normally each acclamation is repeated twice, although additional repetitions remain possible depending upon language, music, or circumstances.
The official texts still permit the ancient Greek words themselves:
Kyrie, eleison.
Christe, eleison.
Kyrie, eleison.
The United States Conference of Catholic Bishops also gives the corresponding English form, “Lord, have mercy. Christ, have mercy. Lord, have mercy.”
After centuries in which Christian worship moved from Greek to Latin and eventually into hundreds of vernacular languages, the original Greek continues to be heard.
A Prayer Shared Across Christian Traditions
The history of the Kyrie cannot be reduced to the Roman Mass.
Its deepest liturgical development began in the Greek-speaking Christian East, where forms of the appeal remain deeply woven into Orthodox and Eastern Christian worship. Repeated responses of Kyrie eleison still accompany litanies in which clergy call the congregation to pray for peace, churches, rulers, travelers, the suffering, the departed, and the needs of the world.
Western Christianity developed the same words differently.
Rome added Christe eleison. Medieval Western musicians expanded the invocation into chant. Monasteries incorporated it into the Hours. Composers wrote polyphonic settings. Reformers retained or translated it. Modern congregations continue to answer with Greek or vernacular equivalents.
Those different histories descend from an extraordinarily simple concept.
Someone names a need.
The people answer by asking for mercy.
That pattern can be seen in the late-fourth-century Apostolic Constitutions. It can be heard through Egeria’s description of children responding in Jerusalem. It appears in the legislation of Vaison, in Benedictine monasteries, in Gregory’s Rome, and in the ceremonial directions of the medieval Church.
Across those centuries, everything surrounding the prayer changed.
The languages changed. Empires disappeared. Churches divided. Musical systems developed. Liturgies were reformed. Congregations began worshipping in languages that Christians of late antiquity had never heard.
The petition survived.
Why “Kyrie Eleison” Matters
Few phrases offer such a compact path through Christian history.
Kyrie eleison connects Scripture with liturgy, East with West, antiquity with the Middle Ages, Catholicism with Protestantism, spoken prayer with musical composition, and modern worshippers with congregations whose voices disappeared more than fifteen centuries ago.
Its history also provides a warning about how ancient Christian traditions should be studied.
The Kyrie did not appear in its final medieval or modern form all at once. The biblical language came first. Eastern Christians used the plea as a response to petitions. Western churches adopted it. Rome developed Christe eleison. Repetitions became increasingly structured. Singers elaborated its music. Medieval theologians supplied layers of interpretation. Reformers preserved it. Modern liturgical reforms altered its arrangement again.
Tradition, in this case, was not simple immobility.
It was continuity through change.
Perhaps the most striking surviving description still comes from Egeria. Standing in Jerusalem in the fourth century, she watched as a deacon named people during prayer and children answered with what she described as seemingly countless voices.
Kyrie eleyson.
For those children, the words were not yet a famous relic from Christian antiquity. They were simply prayer.
More than sixteen centuries later, Christians are still answering with the same words.
Lord, have mercy.
Sources & Further Reading
Apostolic Constitutions. Book VIII, especially chapter 6 and the liturgical litanies. In Ante-Nicene Fathers, vol. 7. Edited by Alexander Roberts, James Donaldson, and A. Cleveland Coxe. Buffalo, NY: Christian Literature Publishing Co., 1886. https://www.newadvent.org/fathers/07158.htm
Aurelian of Arles. Regula ad monachos. Sixth century. https://la.wikisource.org/wiki/Regula_ad_monachos_(Aurelianus_Arelatensis)
Benedict of Nursia. The Rule of Saint Benedict. Chapter 9, “How Many Psalms Are to Be Said at the Night Office.” https://pressbooks.palni.org/ruleofbenedict/chapter/rb-09/
Benedict of Nursia. The Rule of Saint Benedict. Chapter 17, “How Many Psalms Are to Be Sung at These Hours.” https://pressbooks.palni.org/ruleofbenedict/chapter/rb-17/
Bjork, David. “Early Settings of the Kyrie Eleison and the Problem of Genre Definition.” Journal of the Plainsong & Mediaeval Music Society 3 (1980): 40–48. https://doi.org/10.1017/S0143491800000234. https://www.cambridge.org/core/journals/journal-of-the-plainsong-and-mediaeval-music-society/article/abs/early-settings-of-the-kyrie-eleison-and-the-problem-of-genre-definition/8B6268F786536B2AF2B7DBD3F3C473E5
Bishop, Edmund. “Kyrie Eleison.” In Liturgica Historica: Papers on the Liturgy and Religious Life of the Western Church, 116–136. Oxford: Clarendon Press, 1918. https://upload.wikimedia.org/wikipedia/commons/9/98/Liturgica_historica%3B_papers_on_the_liturgy_and_religious_life_of_the_Western_church_%28IA_liturgicahistori00bish%29.pdf
Bradshaw, Paul F., and Maxwell E. Johnson. The Eucharistic Liturgies: Their Evolution and Interpretation. Collegeville, MN: Liturgical Press, 2012. https://books.google.com/books/about/The_Eucharistic_Liturgies.html?id=ms20-mUmdYwC
Cantus Database. “Kyrie Eleison.” University of Waterloo and McGill University. Accessed October 7, 2026. https://cantusdatabase.org/
Colette, Marie-Noël. “The Melodic Nucleus Derived from Anaphoral Chant: ‘Signature Tune’ of Kyrie Eleison Melodies.” Plainsong & Medieval Music 17, no. 2 (2008): 129–146. https://doi.org/10.1017/S0961137108000843. https://www.cambridge.org/core/journals/plainsong-and-medieval-music/article/abs/melodic-nucleus-derived-from-anaphoral-chant-signature-tune-ofkyrie-eleison-melodies/2372A8F30CD3B509F087FCFA573D1D6E
Council of Vaison. “Concilium Vasense II.” 529. Especially canon 3. Wikisource. https://la.wikisource.org/wiki/Concilium_Vasense_%28529%29
De Clercq, Charles, ed. Concilia Galliae A. 511–695. Corpus Christianorum Series Latina 148A. Turnhout: Brepols, 1963.
Egeria. The Pilgrimage of Egeria. Especially 24.5. Translated by M. L. McClure and C. L. Feltoe. London: Society for Promoting Christian Knowledge, 1919. https://ccel.org/m/mcclure/etheria/etheria.htm
Egeria. Itinerarium Egeriae. Latin text, especially 24.5. https://www.tha.de/~harsch/Chronologia/Lspost04/Egeria/ege_it24.html
Fortescue, Adrian. “Kyrie Eleison.” In The Catholic Encyclopedia. Vol. 8. New York: Robert Appleton Company, 1910. https://www.newadvent.org/cathen/08714a.htm
Gregory the Great. Registrum Epistolarum. Book 9, Letter 12, to John of Syracuse. In Nicene and Post-Nicene Fathers, 2nd ser., vol. 13. Translated by James Barmby. Buffalo, NY: Christian Literature Publishing Co., 1898. https://www.newadvent.org/fathers/360209012.htm
Hiley, David. Western Plainchant: A Handbook. Oxford: Clarendon Press, 1993. https://academic.oup.com/book/49864
Jungmann, Josef A. The Mass of the Roman Rite: Its Origins and Development (Missarum Sollemnia). Translated by Francis A. Brunner. 2 vols. New York: Benziger Brothers, 1951. https://books.google.com/books/about/The_Mass_of_the_Roman_Rite.html?id=_S30AAAAMAAJ
Amalarius of Metz. De ecclesiasticis officiis. Patrologia Latina 105. Especially the discussion “De Kyrie eleison.” https://la.wikisource.org/wiki/De_ecclesiasticis_officiis_%28PL_105%29
Ordo Romanus I. Especially the directions concerning the schola and the singing of the Kyrie following the Introit. https://la.wikisource.org/wiki/Ordo_Romanus_I
Andrieu, Michel, ed. Les Ordines Romani du haut moyen âge. 5 vols. Louvain: Spicilegium Sacrum Lovaniense, 1931–1961.
Biblissima. “Bibliothèque nationale de France, NAL 3126.” Medieval manuscript containing Kyrie chants and tropes including Kyrie fons bonitatis and Cunctipotens genitor Deus. Accessed October 7, 2026. https://iiif.biblissima.fr/collections/manifest/e980c90201311049eedae0dec558126b422d36a8
Vogel, Cyrille. Medieval Liturgy: An Introduction to the Sources. Translated and revised by William G. Storey and Niels Krogh Rasmussen, with John K. Brooks-Leonard. Washington, DC: Pastoral Press, 1986. https://books.google.com/books/about/Medieval_Liturgy.html?hl=en&id=TjbZAAAAMAAJ&output=html_text
Usuarium. A Digital Library and Database for the Study of Latin Liturgical History. Eötvös Loránd University. Accessed October 7, 2026. https://usuarium.elte.hu/
Catholic Church. Missale Romanum. 1962. https://isidore.co/misc/Res%20pro%20Deo/ITOPL_OCR-layer-only/11a.%20Liturgy/Missale%20Romanum%201962_OCR.pdf
Catholic Church. “General Instruction of the Roman Missal.” Especially sec. 52, “The Kyrie, Eleison.” Vatican. https://www.vatican.va/roman_curia/congregations/ccdds/documents/rc_con_ccdds_doc_20030317_ordinamento-messale_en.html
United States Conference of Catholic Bishops. “Mass Settings: Texts.” Accessed October 7, 2026. https://www.usccb.org/committees/divine-worship/policies/mass-settings-texts
Konziliengeschichte. “Vasense / Vaison.” Concilia: A Database of Early Church Councils. Accessed October 7, 2026. The entry confirms the council met in 529 and that canon 3 prescribed the Kyrie at Matins, Mass, and Vespers. Konziliengeschichte https://www.konziliengeschichte.org/site/de/publikationen/lexikon/database/666.html