Mission to the Slavs with his brother Methodius Rome 9th century

St. Cyril of Thessalonica

Cyril brought the Gospel to Slavic peoples in a language they could hear and died in Rome before his brother Methodius continued their mission.

Lifespan
c. 827 - 869 lived about 42 years
Feast day
February 14
Principal shrine
Basilica of San Clemente al Laterano, Rome Rome, Italy
Known for
Mission to the Slavs with his brother Methodius, Translation and the development of Slavic liturgical writing
01 · The Life and Witness

The Life and Witness of Cyril of Thessalonica.

Pilgrims descend at San Clemente in Rome to venerate Saint Cyril, the brother of Methodius. The basilica holds the end of a life spent crossing languages, courts, and Church boundaries for the Gospel.

Born Constantine in Thessalonica around 827, Cyril was educated in the Byzantine world and joined his brother Methodius in missions beyond it. Their work among Slavic peoples required more than a sermon in translation. They prepared a written language and liturgical texts so the faith could be proclaimed and prayed in the people’s own tongue.

The brothers traveled to Rome, where their work received papal attention and support. Cyril took monastic vows and his religious name near the end of his life. He died there in 869; Methodius returned to continue the mission. Their biographies belong together, but Cyril’s death in Rome and Methodius’s later episcopal work are distinct chapters.

San Clemente preserves Cyril’s tomb and relics. John Paul II named both brothers co-patrons of Europe in 1980 and later reflected on their service to Christian unity. The pilgrim at Cyril’s tomb can pray for a Church that speaks the Gospel faithfully across languages without surrendering its unity.

Cyril treated language as a way to serve the person receiving the Gospel. His Rome tomb also holds the memory of a mission that crossed the Christian East and West.

02 · A Life in Time

A life, in years and approximate ages.

  1. c. 827
    Birth
    Born in Thessalonica
    Constantine, later known as Cyril, is born in the Byzantine city; the date is approximate.
  2. 860
    Mission beyond Byzantium
    He undertakes diplomatic and missionary work before the Moravian mission.
  3. 863
    Sent to Great Moravia
    Cyril and Methodius prepare Slavonic texts for evangelization and worship.
  4. 867
    Travels to Rome
    The brothers bring their work into conversation with the Roman Church.
  5. 869
    At death
    Dies in Rome
    Cyril takes monastic vows and dies on February 14; he is buried at San Clemente.
  6. 1980
    After death
    Named co-patron of Europe
    John Paul II names Cyril and Methodius co-patrons of Europe.

Dates are approximate where the surviving record is traditional or incomplete.

03 · Where to Go

One place where this witness remains visible.

04 · How to Encounter

Visit Basilica of San Clemente al Laterano, Rome

Descend through San Clemente’s historical layers and stop at Cyril’s tomb for prayer for the unity of Christians.

Begin with prayer

Descend through San Clemente’s historical layers and stop at Cyril’s tomb for prayer for the unity of Christians.

Read the place

Pilgrims venerate the tomb and relics of the missionary Cyril in the basilica.

05 · Tomb & Relics

Tomb and relics at San Clemente

Cyril was buried in Rome in 869. San Clemente preserves and presents his tomb and relics for veneration. This is Cyril of Thessalonica, brother of Methodius, not Cyril of Jerusalem or Cyril of Alexandria.

Relic tradition
Publicly venerated

A principal relic site is named, with other fragments or reliquaries noted separately.

07 · Feast & Devotion

Kept on February 14.

The Church commemorates Saint Cyril of Thessalonica on February 14.

Descend through San Clemente’s historical layers and stop at Cyril’s tomb for prayer for the unity of Christians.

08 · Notes & Sources Sources and notes.

We rely on primary writings, official Church and shrine sources, and careful traditional accounts where modern documentation is limited.

Dates and relic traditions are named plainly when they are approximate, traditional, or contested.

Church sources

Shrine sources

Further reading

Photo credits
  1. Saint page. Unknown medieval artist, public domain, via Wikimedia Commons. Source. Public Domain.
  2. Basilica of San Clemente al Laterano, Rome. Ninfamania / Wikimedia Commons (CC BY 4.0). Source. CC BY 4.0.