Saints Cyril and Methodius: The Brothers Behind Slavic Writing

Saints Cyril and Methodius were Byzantine brothers who gave the Slavs their first written language. Born in Thessaloniki in the 9th century, they led a mission to Great Moravia in 863 and translated church books into Slavic. In Bulgarian they are Свети Кирил и Методий (Sveti Kiril i Metodiy), and Britannica calls them “the Apostles of the Slavs.”

Early lives in Thessaloniki

Methodius was the elder brother, born around 815. Cyril was born around 827 and baptized Constantine. He took the name Cyril only near the end of his life, when he became a monk. Scholars often call him Constantine the Philosopher, after his reputation as a teacher in Constantinople.

Thessaloniki, then a major Byzantine city, had a large Slavic-speaking population around it. The brothers grew up knowing that local Slavic speech. That knowledge later made them the natural choice for a Slavic mission.

Before Moravia, Constantine traveled on a diplomatic and religious mission to the Khazars, around 860. Methodius had served as a regional administrator before becoming a monk.

The mission of Saints Cyril and Methodius to Great Moravia

In 862, Prince Rastislav of Great Moravia asked the Byzantine emperor for missionaries who could teach in the Slavic language. Rastislav wanted to reduce his country’s dependence on East Frankish clergy, who used Latin.

The brothers arrived in 863. For the task, Constantine created a new script, the Glagolitic alphabet, designed for Slavic sounds. With it they translated the Gospels and the main church services into the language now known as Old Church Slavonic.

Using a Slavic liturgy was controversial. Some Western clergy held that only Hebrew, Greek and Latin were fit for worship. In 867 to 868 the brothers traveled to Rome, where Pope Adrian II gave papal support to their Slavonic books.

Cyril’s death and Methodius’s later work

Constantine fell ill in Rome. He took monastic vows and the name Cyril, and died there on 14 February 869. He was buried in the Basilica of San Clemente in Rome.

Methodius carried on. Around 869 to 870 he became Archbishop of Sirmium, with authority over the Slavic mission. His opponents among the Frankish clergy had him imprisoned for about two and a half years, until Pope John VIII secured his release in 873. In 878 he was cleared of heresy charges in Rome and allowed to continue the Slavonic liturgy.

Methodius died on 6 April 885. Most sources give 885, though Britannica’s biography gives 884.

How the brothers’ work reached Bulgaria

Without Methodius, the mission collapsed. His disciples were expelled from Great Moravia around 885 to 886. Several, including Clement, Naum and Angelarius, crossed into the First Bulgarian Empire, where Prince Boris I welcomed them.

Boris had made Bulgaria Christian in the 860s and wanted a church that used the people’s own language instead of Greek. The disciples gave him that. Clement taught at Ohrid from 886 to 893, and Naum worked in Pliska and later Preslav.

In Preslav, scholars soon developed a new script based on Greek capitals, the Cyrillic alphabet. It carries Cyril’s name as a tribute, although he did not design it. Our page on who invented Cyrillic covers the scholarly debate.

Feast days and honors

Saints Cyril and Methodius are honored in both Eastern and Western Christianity.

• Roman Catholic, Anglican and Lutheran churches: 14 February, the date of Cyril’s death. Pope Leo XIII added their feast to the Roman calendar in 1880.
• Eastern Orthodox churches: 11 May.
• Bulgaria: 24 May is a national holiday for the Bulgarian alphabet, education and culture. See our page on the Day of the Bulgarian Alphabet.

On 31 December 1980, Pope John Paul II named the brothers co-patrons of Europe, alongside Saint Benedict of Nursia, in the apostolic letter Egregiae Virtutis. In 1985 he followed it with a whole encyclical, Slavorum Apostoli, marking 1,100 years since the death of Methodius.

The legacy of Saints Cyril and Methodius in Bulgaria

No country has built more of its identity around the brothers than Bulgaria, even though they never worked there. Their names appear across public life.

• The national library in Sofia is the Национална библиотека „Св. св. Кирил и Методий“ (Natsionalna biblioteka “Sv. sv. Kiril i Metodiy”), with a statue of the brothers outside.
• Schools, streets and the university in Veliko Tarnovo carry their names.
• On 24 May, students and teachers march in processions with flowers, often carrying portraits of the two saints.

The holiday’s official Bulgarian name begins with Ден на светите братя Кирил и Методий (Den na svetite bratya Kiril i Metodiy), “Day of the Holy Brothers Cyril and Methodius.” It shows how closely Bulgarians link the brothers to the alphabet they read every day.

Contested identities

Modern nations sometimes claim the brothers as their own. Greek sources stress their Byzantine origin. Bulgarian, Macedonian, Czech, Slovak and Russian traditions all honor them as founders of Slavic letters. Historians generally describe them simply as Byzantine Greeks from Thessaloniki who spoke the local Slavic dialect. That is the safest summary of what the evidence shows.

Common mistakes about Saints Cyril and Methodius

• Saying they invented Cyrillic. Cyril created Glagolitic. Cyrillic was developed by their disciples in Bulgaria.
• Saying they worked in Bulgaria. The brothers’ mission was in Great Moravia and Pannonia. Their disciples, not the brothers themselves, worked in Bulgaria.
• Calling Cyril by that name throughout his life. He was Constantine until he became a monk shortly before his death in 869.
• Mixing up the feast dates. 14 February is the Western feast, 11 May the Orthodox one, and 24 May the Bulgarian civic holiday.

To follow the story from the brothers to today’s 30 letters, read our Bulgarian alphabet history.

Frequently asked questions

Who were Saints Cyril and Methodius?

They were Byzantine brothers from Thessaloniki who led a Christian mission to the Slavs of Great Moravia from 863. They created the first Slavic script and translated church texts into Slavic.

Did Cyril and Methodius create the Cyrillic alphabet?

Not directly. Cyril created the Glagolitic alphabet. Cyrillic was developed later by their disciples in the First Bulgarian Empire and named in Cyril’s honor.

Were Cyril and Methodius Bulgarian?

Historians describe them as Byzantine subjects from Thessaloniki, generally regarded as Greek, who knew the local Slavic dialect. Their legacy is strongest in Bulgaria because their disciples settled there.

When is the feast of Saints Cyril and Methodius?

14 February in the Catholic, Anglican and Lutheran churches, and 11 May in the Orthodox Church. Bulgaria also marks 24 May as a national holiday in their honor.

Why are Cyril and Methodius patron saints of Europe?

Pope John Paul II named them co-patrons of Europe in 1980, alongside Saint Benedict, to honor their role in bringing Christianity and literacy to the Slavic peoples.

Sources

• Britannica: Saints Cyril and Methodius
• Wikipedia: Saints Cyril and Methodius
• Wikipedia: Clement of Ohrid
• Vatican: Slavorum Apostoli, encyclical of John Paul II (1985)

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