St Cyril and Methodius

They were brothers from Salonica, of eminent and wealthy parents, Leo and Maria. The elder brother, Methodius, spent ten years as an officer among the Slavs in Macedonia, and thus learned the Slavic language. After that, Methodius went off to Olympus and gave himself to monastic asceticism, and Cyril (Constantine) later joined him there. When the Khazarite king, Kagan, sought preachers of the Christian faith from the Emperor Michael, the Emperor commanded that these two brothers be found and sent to the Khazars. They converted Kagan to the Christian faith and baptised him, together with a great number of his nobles and an even greater number of the people.

After some time, they returned to Constantinople, where they compiled a Slavic alphabet of 38 letters and began to translate the service books from Greek into Slavonic. At the invitation of Prince Rastislav, they went to Moravia, where, with great devotion, they spread and confirmed the Faith, made more copies of the books, brought them priests and taught the young. They went to Rome at the invitation of the Pope, and Cyril fell ill and died there, on February 14th, 869. Then Methodius returned to Moravia and laboured at the confirming of the Faith among the Slavs until his death. After his death - he entered into rest in the Lord on April 6th, 885 - his disciples, the Five Followers, with St Clement as bishop at the beginning, crossed the Danube and moved towards the south, to Macedonia, where, from Ochrid, they continued the work among the Slavs that Cyril and Methodius had begun in the north.

source: www.crkvenikalendar.com