The Mission to the Slavs
The decisive act of Rostislav's reign was his appeal to Constantinople for missionaries who could teach in the Slavic language. According to the tradition, his people had already rejected paganism and adhered to the Christian law, but lacked a teacher who could explain the faith in their own tongue. The request was bound up with his political situation: turning to Byzantium offered an alternative to the Frankish Latin clergy whose presence reinforced East Frankish influence, and historians regard his motives as at once religious and political.
The brothers Cyril and Methodius answered this call in 863. Rather than impose Greek or Latin, they conducted teaching and worship in Slavonic, and Cyril created an alphabet — the Glagolitic script — suited to the sounds of the Slavic language. Their translations of Scripture and the liturgical books laid the foundation of Slavonic literature and of the liturgical use of Church Slavonic among the Slavic peoples. In Orthodox memory, Rostislav's petition is the human occasion of this enduring work.