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863 CEPrimary source · 2 sourcesWell documented

Cyril and Methodius Bring Christianity and a New Alphabet to the Slavs

Two Byzantine brothers invent a script to translate scripture for Slavic-speaking Moravia

On the timeline · around 863 CE · Iconoclasm and RecoveryIconoclasm and RecoveryThe Macedonian Golden AgeCyril and Methodius Bring Christianity and a New Alphabet to the Slavs825 CE850 CE875 CE900 CE925 CE

Quick facts

Missionaries
Cyril (Constantine) and Methodius
Sent by
Emperor Michael III
Mission began
863 CE
Script created
Glagolitic, ancestor of Cyrillic

What happened

Constantine, later known by his monastic name Cyril, was born in Thessaloniki and educated in Constantinople, where he studied under the Patriarch Photios and taught philosophy at the Magnaura university, earning the title Constantine the Philosopher. In 863 CE, Prince Rastislav of Moravia requested Byzantine missionaries, and Emperor Michael III sent Cyril along with his older brother Methodius to preach Christianity to the Slavs. Because no writing system existed that could accurately represent Slavic sounds, Cyril devised the Glagolitic alphabet, borrowing elements from Hebrew and Greek cursive script, to translate scripture and liturgy into the Slavic vernacular. Their students at the Preslav Literary School later simplified Glagolitic into what became the Cyrillic alphabet, named for Cyril, drawing more heavily on Greek letterforms.

Why it matters

The Cyrillic alphabet that descended from Cyril's work is still used today across Russia, Bulgaria, Serbia, and other Slavic-language countries, and the brothers' mission tied the Slavic world's religious and literary culture to Byzantine Christianity rather than the Latin west.

How we know

The World History Encyclopedia's biography of Saint Cyril documents his education, the 863 CE mission at Rastislav's request, and his creation of the Glagolitic script as the direct ancestor of Cyrillic.

Sources

  • World History Encyclopedia. Saint Cyril · Reputable sourceworldhistory.org · The domain "worldhistory.org" is on our Reputable source registry. · Link is live and its text matches the event's key terms (Jul 2026)
  • Dumbarton Oaks. Michael III (856-867) · Primary source (author-declared)doaks.org · Cited as a "primary" source (no stronger domain match). · Link is live and its text matches the event's key terms (Jul 2026)

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