mission · 863 · Great Moravia
In 863 the brothers Constantine (Cyril) and Methodius of Thessalonica reached Moravia with a script fitted to Slavic speech and the liturgy in the people's tongue. Driven out by Frankish clergy, their disciples carried the work to Bulgaria — where the Cyrillic alphabet matured and the Slavic Orthodox world found its voice.
The Slavonic letters and liturgy — the alphabet of the Orthodox Slavic world.