Sts Cyril and Methodius, Apostles to the Slavs

Every time a Russian, Serbian, Bulgarian or Ukrainian Christian opens a prayer book, the letters on the page carry the name of a ninth-century Greek monk. Sts Cyril and Methodius, two brothers from Thessalonica, gave the Slavs an alphabet, a written language and a liturgy they could understand. The Orthodox Church calls them Equal-to-the-Apostles and Enlighteners of the Slavs; the Roman Catholic Church has named them co-patrons of Europe.

Their story is also one of the clearest windows we have onto the Church before the schism of East and West. The brothers were sent by the emperor and patriarch in Constantinople, welcomed by the pope in Rome, opposed by Frankish bishops, and buried in two different churches. This article tells their story as the Church remembers it, checks it against the earliest sources and modern scholarship, and asks what their mission meant for both East and West.

In brief

Constantine (later Cyril) and his elder brother Methodius were born in Thessalonica in the early ninth century. Constantine became a scholar in Constantinople, called "the Philosopher"; Methodius served as a governor of a Slav-populated province and then became a monk. Around 862, Prince Rastislav of Great Moravia asked Emperor Michael III for a teacher who could instruct his people in their own language. The brothers arrived in 863 with a new alphabet, now called Glagolitic, and Slavonic translations of the Gospels and services. Opposed by Frankish clergy, they traveled through Venice, where Constantine defended worship in Slavonic against the "trilingual" view, to Rome, where Pope Hadrian II approved their books. Constantine became a monk named Cyril and died in Rome in 869. Methodius was consecrated archbishop, imprisoned by Frankish bishops, freed by Pope John VIII, and died in Moravia in 885. His disciples, expelled, carried the work to Bulgaria, where the Cyrillic alphabet was developed and named after Cyril. They are venerated in both East and West.

Thesis: Cyril and Methodius were Byzantine missionaries of the undivided Church whose conviction that every people may praise God in its own tongue was upheld by Constantinople and, for a time, by Rome, and became the foundation of Slavic Orthodox Christianity.

The life as the Church tells it

Two brothers from Thessalonica

The Orthodox Church in America's Life of the brothers says they came "from an illustrious and pious family" in Thessalonica, Methodius the eldest of seven brothers and Constantine the youngest. Methodius served as governor in a Slavic principality under Byzantine rule, which allowed him to learn the language, and then became a monk on Mount Olympus in Asia Minor.¹ The Encyclopedia of Ukraine gives Constantine's birth as 827.²

Constantine studied in Constantinople under the finest teachers, including the future Patriarch Photios, and his learning earned him the name "the Philosopher." The historian Francis Dvornik notes that he later succeeded Photios as a teacher of philosophy.³ The site's article on St Photios the Great describes the patriarch under whom the Moravian mission was sent. The emperor used Constantine as an envoy, first to the Arabs and then, with Methodius, to the Khazars north of the Black Sea, around 860 to 861. On the way, at Cherson in the Crimea, the brothers recovered relics believed to be those of St Clement of Rome, which they carried with them for the rest of the mission.²³

The call from Moravia

Great Moravia, a Slavic state in what are now the Czech Republic and Slovakia, was already partly Christian. Frankish missionaries from Bavaria had worked there for decades. Its ruler, Rastislav, wanted a church of his own, not one directed from the Frankish empire. The Life of Methodius reports his message to Emperor Michael III, here as quoted by Pope John Paul II: "Many Christian teachers have reached us from Italy, from Greece and from Germany, who instruct us in different ways. But we Slavs ... have no one to direct us towards the truth and instruct us in an understandable way."⁴ In the English rendering of Todd Krause and Jonathan Slocum (University of Texas), the emperor explains his choice: "You two are from Salonika, and all Thessalonians speak pure Slavonic."⁵

Before leaving, Constantine devised an alphabet for the Slavonic language and began translating the Gospels and the services. He arrived in Moravia in 863 and began training young men for the priesthood. {{strong: The mission to Great Moravia began in 863, at Rastislav's request, and brought a newly invented Slavonic alphabet and translated liturgical books.}}

Venice, Rome and the death of Cyril

The Frankish clergy objected. After about three years the brothers left Moravia, stopping in Pannonia, where Prince Kocel entrusted about fifty young men to them for instruction, and then in Venice.³ There Constantine faced clergy who held that God could be praised in writing only in three languages, Hebrew, Greek and Latin. His reply, in the Life of Constantine (chapter 16), is the classic statement of the brothers' cause. In Krause and Slocum's English rendering:

Are ye not ashamed to mention only three tongues, and to command all other nations and tribes to be blind and deaf? Tell me, render ye God powerless, that He is incapable of granting this? or envious, that He desires this not?⁵

He went on to name peoples who already praised God in their own tongues: Armenians, Persians, Abkhazians, Iberians (Georgians), Goths and others. The same speech quotes a long passage of 1 Corinthians 14, where St Paul says, "yet in the church I would rather speak five words with my understanding, that I may teach others also, than ten thousand words in a tongue" (1 Corinthians 14:19, NKJV).⁶⁷ At Pentecost the crowds asked, "how is it that we hear, each in our own language in which we were born?" (Acts 2:8, NKJV).

The brothers reached Rome late in 867. Pope Nicholas I had just died, and his successor Hadrian II received them warmly, above all because they brought the relics of St Clement. According to John Paul II's summary of the sources, Hadrian "approved the Slavonic liturgical books, which he ordered to be solemnly placed on the altar in the Church of Saint Mary ad Praesepe," today St Mary Major, and their disciples were ordained.⁴ Dvornik adds that the Slavonic liturgy was celebrated in Rome itself in 868.³

Constantine, never strong, fell gravely ill. He received the monastic habit and the name Cyril, and died on February 14, 869.⁴¹ The Life of Methodius records his last words to his brother: "Behold, my brother, we have shared the same destiny, ploughing the same furrow; I now fall in the field at the end of my day. I know that you greatly love your Mountain; but do not for the sake of the Mountain give up your work of teaching."⁴ Methodius asked to take the body home, but the pope had Cyril buried in the Roman basilica of St Clement, where his relics are venerated today.¹

Methodius: archbishop and prisoner

Hadrian II consecrated Methodius archbishop of Sirmium, the ancient see of Pannonia, with authority over Pannonia and Moravia and the role of papal legate to the Slavs.⁴ The Frankish bishops regarded this as an invasion of their territory. They seized him, condemned him at a local synod, and confined him in a monastery in Swabia, which Dvornik thought was probably Ellwangen. Only in 873 did Pope John VIII learn what had happened and secure his release.³ John Paul II describes his "imprisonment for two years, on the charge of having invaded the episcopal jurisdiction of another"; the OCA Life speaks of two and a half years in chains.⁴¹ Marco Scarpa notes that the names of Methodius and his disciples appear in the confraternity book of the abbey of Reichenau and suggests the confinement was probably an enforced stay there, as respected guests, rather than a prison in the modern sense.⁷

Back in Moravia, Methodius faced a new ruler, Svatopluk, who preferred the Latin Mass, and a German cleric, Wiching, whom John VIII made bishop of Nitra at Svatopluk's request and who accused Methodius in Rome. In 880 John VIII cleared him and, in the letter Industriae tuae, praised the "Slavonic letters" invented by Constantine and ordered that Christ's praises be proclaimed in that language, "for we are admonished by sacred authority to praise the Lord not in three languages only, but in all."⁷ In 881 or 882 Methodius visited Constantinople, where the emperor and Patriarch Photios received him and asked him to leave Slavonic books and clergy in the capital.⁴³ In his last years he and his disciples translated most of the Old Testament, a collection of church law and other works. He died on April 6, 885.³¹

The disciples and the birth of Cyrillic

The work in Moravia nearly collapsed. Wiching obtained from the next pope, Stephen (called Stephen VI by Dvornik and the OCA), a condemnation of the Slavonic liturgy. The disciples were imprisoned and those of Byzantine origin, including Clement, Naum, Angelarius and Laurentius, were expelled; according to the Life of Naum, some were sold as slaves in Venice and ransomed by a Byzantine official.³⁸

Several of them found refuge in Bulgaria, whose ruler Boris, baptized in 864, welcomed them. St Clement trained thousands of students and became the first bishop in Bulgaria to preach and write in Slavonic; he died at Ohrid in 916.⁸ Schools at Preslav and Ohrid produced a flood of translations from Greek.³ In this setting the disciples adapted the Greek alphabet, adding letters from Glagolitic for Slavic sounds. This new script, probably developed at Preslav, was named "Cyrillic" in honor of the man who had created the first Slavic alphabet.⁹ From Bulgaria the Slavonic books passed to Serbia and to Kyivan Rus, where they served the baptism of the Rus in 988, some 125 years after the Moravian mission (see St Vladimir and the Baptism of Rus).⁴

The primary historical evidence

The two main sources are the Slavonic Life of Constantine and Life of Methodius, written within the circle of the brothers' disciples. The Encyclopedia of Ukraine credits Methodius himself with completing a biography of Cyril.¹⁰ They are hagiography, written to defend the mission, but historians take their core seriously. Dvornik, a leading twentieth-century specialist, draws heavily on them while noting their limits: the biographers say nothing of the mission's political background because "Byzantine hagiographers were only interested in the religious deeds of their heroes."³

Other evidence comes from outside the brothers' circle. Papal letters survive, including John VIII's Industriae tuae of 880, preserved in the Latin collections of papal correspondence.⁷ Hadrian II's letter to the Slavic princes survives only in a Slavonic version inside the Life of Methodius, but Dvornik writes that "Its genuineness is, however, generally accepted by specialists."³ Frankish sources record the complaints of the Bavarian bishops, and the Greek Life of St Clement is the main source for the disciples' expulsion.³ Archaeology has added a further check: Dvornik reported the foundations of sixteen stone churches in Moravia, at least five built before the Byzantine mission arrived, which confirms Rastislav's claim that his people were already Christian.³

What can we actually verify?

(a) Contemporary or near-contemporary documentary evidence

The main events are well attested: the request from Moravia, the mission of 863, the visit to Rome and Hadrian II's approval, Cyril's death in Rome on February 14, 869, Methodius's appointment as archbishop, his detention by Frankish bishops and release through John VIII, John VIII's renewed approval in 880, Methodius's death on April 6, 885, and the expulsion of the disciples. {{very-strong: Pope John VIII's letter of 880 approved the use of Slavonic in the liturgy, defending praise of God "not in three languages only, but in all."}} The date 863 and Constantine's authorship of the first Slavic alphabet are accepted by specialists; Dvornik wrote that they "are now almost unanimous" that his alphabet was the Glagolitic, not the later Cyrillic.³

(b) Later hagiographical tradition

The OCA's Life of Cyril dates the Khazar mission to 857, while Dvornik and the Encyclopedia of Ukraine place it in 860 or 861.¹¹² The OCA's Lives also say the brothers devised the alphabet "by a revelation from God," that Pope Hadrian came out to meet them on the road, and that Methodius's funeral was sung in Slavonic, Greek and Latin.¹¹¹ These belong to the Church's devotional memory. The OCA's Life also says that one of the Frankish persecutions came because Methodius "did not accept the erroneous teaching about the procession of the Holy Spirit from both the Father and the Son."¹ On the doctrine the Life is right: the Filioque is an error. Christ says that the Spirit "proceeds from the Father" (John 15:26, NKJV), the Creed of 381 confesses exactly that, and the Father is the one source of the Son and the Spirit. What is less clear historically is how large the Filioque loomed in Moravia: Dvornik's account of the conflict centers on jurisdiction and the Slavonic liturgy.

(c) Reported miracles

The Lives report prophecies and wonders, and the OCA says miracles occurred at Cyril's tomb in Rome.¹ These are part of the Church's witness to their holiness. The brothers' fame, however, rests chiefly on work anyone can still see: an alphabet, a literary language and a living liturgy.

The Orthodox position

The Orthodox Church honors Cyril and Methodius as Equal-to-the-Apostles and Teachers of the Slavs. They are commemorated together on May 11, Cyril also on February 14, the day of his death, and Methodius on April 6.¹¹¹¹² Their disciples Clement, Naum, Sava, Gorazd and Angelarius are venerated as well; St Clement of Ohrid is commemorated on July 27.⁸

For the Orthodox, the brothers show a principle the Church holds dear: the Gospel is meant to be heard in the language of the people. Dvornik puts the point plainly: "The brothers were not of the Roman but of the Byzantine obedience and were following, in their innovations, the custom of the Eastern Church."³ The same instinct explains why the Slavic churches pray in Church Slavonic rather than Greek, and why the Divine Liturgy (see the site's beginner's guide) has never been bound to a single sacred language.

The Church's recognition of the brothers is a matter of common tradition and liturgical practice. As with any saint (see How Does Someone Become a Saint?), it affirms their holiness and invites the faithful to ask their prayers (see Why Do Orthodox Christians Pray to Saints?), without making every detail of the Lives a matter of faith.

The strongest objections

"They were papal missionaries, so their legacy belongs to Rome"

A Catholic reader can point out that the brothers went to Rome, that Hadrian II approved their books, ordained their disciples and made Methodius an archbishop, and that John VIII defended him. All of this is true and should be stated without embarrassment. John Paul II's encyclical Slavorum Apostoli (1985) presents them as "the connecting links or spiritual bridge between the Eastern and Western traditions."⁴ The Orthodox reply is not to deny the Roman chapter but to place it in the undivided Church of the ninth century, before Rome added the Filioque to the Creed and before the later claims of papal supremacy. The brothers were sent by Constantinople and trained there, and Methodius later visited its patriarch; around 882 Photios, who, as John Paul II notes, "was in full communion with Rome," received Methodius and asked for Slavonic books.⁴ Rome rightly honors them. But the faith they preached, with the Creed unaltered and worship in the people's own tongue, is the faith the Orthodox Church still keeps, and the churches their disciples founded are Orthodox churches to this day.

"The mission was political"

A skeptic may say Rastislav wanted Byzantine help against the Franks and Bulgarians, and that Constantinople wanted influence in central Europe. Dvornik largely agrees that the mission had a political aspect, an alliance against the Frankish-Bulgarian pact.³ Yet political motives do not cancel religious ones. The brothers spent their lives on translation and teaching in hostile territory, and Methodius went to confinement rather than abandon the Slavonic liturgy.

"Rome itself held the trilingual view"

Some Orthodox polemic presents the "trilingual heresy" as the teaching of the papacy. The record is more complicated. Hadrian II and John VIII approved Slavonic worship; the opposition came mainly from Frankish bishops, and the later ban came under a pope whom Dvornik believed was deceived by Wiching.³ The honest summary is that Rome wavered, while Constantinople welcomed the Slavonic books and clergy. Even in the West the work did not vanish: Dvornik notes Glagolitic missals "still used in some places in Yugoslavia" in his day.³

"The Lives are legend, not history"

Hagiography has its purposes, and the Lives defend the brothers against their critics. But they can be checked: against papal letters, Frankish complaints, the Greek Life of Clement, the surviving Slavonic texts and the archaeology of Moravia. On the main events, these sources agree.

What we can say confidently

• Constantine-Cyril and Methodius were brothers from Thessalonica, sent from Constantinople to Great Moravia in 863 at Rastislav's request.
• Constantine created the first Slavic alphabet, Glagolitic; Cyrillic was developed later by their disciples, probably in Bulgaria, and named in his honor.
• Pope Hadrian II approved their Slavonic books; Pope John VIII confirmed the Slavonic liturgy in 880.
• Cyril died in Rome on February 14, 869, and is buried in the Basilica of St Clement; Methodius died on April 6, 885.
• Methodius was detained for several years by Frankish bishops and freed through John VIII.
• Their disciples, expelled from Moravia, carried Slavonic Christianity to Bulgaria, from where it reached Serbia and Rus.
• They are venerated as saints by both the Orthodox and Roman Catholic Churches.

What remains disputed

• The date of the Khazar mission (857 or 860 to 861).
• Whether the Slavonic Mass first used in Moravia was a Byzantine liturgy or, as Dvornik argued, an adaptation of the Greek translation of the Latin Mass (the liturgy of St Peter), supplemented by a Latin formulary.
• The exact place and nature of Methodius's detention (Ellwangen according to Dvornik, Reichenau according to Scarpa; harsh prison or enforced monastic stay).
• How large a role the Filioque played in the Frankish opposition (a historical question; the Filioque itself is an error).
• The weight to give the political motives on both sides.

Conclusion

Cyril and Methodius did not set out to found national churches. They set out to teach. Constantine's question in Venice still stands: why should any nation be left "blind and deaf" before God? The Church answered by treasuring their work, and the answer has borne fruit for more than a thousand years in the churches of the Slavs.

They also remind East and West of a time when a Greek monk could be ordained in Rome, buried beside a pope's relics, and remembered with love in Constantinople, Sofia and Moscow. For the Orthodox, their feast is a call to keep the faith of the apostles in a language people can understand, and to pray for the unity of all who confess the Father, the Son and the Holy Spirit. Readers can find more of the Church's saints in the site's lives of the saints.

Notes

1. Orthodox Church in America, "Equals of the Apostles and Teachers of the Slavs Cyril and Methodius," Lives of the Saints (commemorated May 11), https://www.oca.org/saints/lives/2025/05/11/101350-equals-of-the-apostles-and-teachers-of-the-slavs-cyril-and-metho.
2. George Y. Shevelov, "Saint Cyril," Internet Encyclopedia of Ukraine (Canadian Institute of Ukrainian Studies), https://www.encyclopediaofukraine.com/display.asp?linkpath=pages%5CS%5CA%5CSaintCyril.htm.
3. Francis Dvornik, "The Significance of the Missions of Cyril and Methodius," Slavic Review 23, no. 2 (June 1964): 195-211, https://archive.org/details/Dvornik1964CyrilMethodius.
4. John Paul II, encyclical Slavorum Apostoli (June 2, 1985), nos. 1, 5-6, 9, 13, 27, https://www.vatican.va/content/john-paul-ii/en/encyclicals/documents/hf_jp-ii_enc_19850602_slavorum-apostoli.html (quoting the Life of Methodius 5 and 6).
5. Todd B. Krause and Jonathan Slocum, Old Church Slavonic Online, Lesson 3, Linguistics Research Center, University of Texas at Austin, https://lrc.la.utexas.edu/eieol/ocsol/30 (English renderings of the Lives credited to the lesson's authors; no other translator or edition is named. The Venice speech is chapter 16 of the Life of Constantine).
6. 1 Corinthians 14:19, Acts 2:8 and John 15:26, New King James Version.
7. Marco Scarpa, "Un contributo per l'interpretazione della citazione di 1 Cor 14 nella controversia veneziana della Vita Cyrilli," in Kirilo-Metodievski studii 26 (Sofia: Cyrillo-Methodian Research Centre, 2018), https://iris.unive.it/bitstream/10278/3701716/1/Studii26Scarpa.pdf (with the Latin text of John VIII, Industriae tuae, from MGH Epistolae; the English rendering of the Latin is the author's).
8. Orthodox Church in America, "Saint Clement of Ochrid, Equal of the Apostles, Bishop of Greater Macedonia" (commemorated July 27), https://www.oca.org/saints/lives/2025/07/27/102103-saint-clement-of-ochrid-equal-of-the-apostles-bishop-of-greater.
9. George Y. Shevelov, "Cyrillic alphabet," Internet Encyclopedia of Ukraine, https://www.encyclopediaofukraine.com/display.asp?linkpath=pages%5CC%5CY%5CCyrillicalphabet.htm; see also "Glagolitic alphabet," https://www.encyclopediaofukraine.com/display.asp?linkpath=pages%5CG%5CL%5CGlagoliticalphabet.htm.
10. "Saint Methodius," Internet Encyclopedia of Ukraine, https://www.encyclopediaofukraine.com/display.asp?linkpath=pages%5CS%5CA%5CSaintMethodius.htm.
11. Orthodox Church in America, "Repose of Saint Cyril, Equal of the Apostles and Teacher of the Slavs" (commemorated February 14), https://www.oca.org/saints/lives/2025/02/14/100519-repose-of-saint-cyril-equal-of-the-apostles-and-teacher-of-the-s.
12. Orthodox Church in America, "Saint Methodius, Equal of the Apostles, Archbishop of Moravia" (commemorated April 6), https://www.oca.org/saints/lives/2025/04/06/101009-saint-methodius-equal-of-the-apostles-archbishop-of-moravia-enli.

Bibliography

Primary sources

• The Holy Bible, New King James Version. Nashville: Thomas Nelson, 1982.
• Life of Constantine (Vita Constantini) and Life of Methodius (Vita Methodii), Old Church Slavonic; passages as quoted in English by John Paul II and by Krause and Slocum.
• John VIII. Industriae tuae (880). Latin text in MGH Epistolae, as reproduced by Scarpa (2018).

Orthodox and patristic sources

• Orthodox Church in America. Lives of the Saints: Cyril and Methodius (May 11); Repose of St Cyril (February 14); St Methodius (April 6); St Clement of Ohrid (July 27). oca.org.

Other scholarship (including scholars who disagree)

• Dvornik, Francis. "The Significance of the Missions of Cyril and Methodius." Slavic Review 23, no. 2 (1964): 195-211.
• Krause, Todd B., and Jonathan Slocum. Old Church Slavonic Online. Linguistics Research Center, University of Texas at Austin.
• Scarpa, Marco. "Un contributo per l'interpretazione della citazione di 1 Cor 14 nella controversia veneziana della Vita Cyrilli." Kirilo-Metodievski studii 26. Sofia, 2018.
• Shevelov, George Y., and others. "Saint Cyril," "Saint Methodius," "Cyrillic alphabet," "Glagolitic alphabet." Internet Encyclopedia of Ukraine. Canadian Institute of Ukrainian Studies.

Sources from the traditions discussed (Roman Catholic)

• John Paul II. Slavorum Apostoli. Encyclical, June 2, 1985.