Methodius of Thessalonica

Methodius was the elder brother, born at Thessalonica around 815, and his early career was administrative rather than scholarly. He governed a Slav-populated district before withdrawing to a monastery on Mount Olympus in Bithynia. He joined his brother for the Khazar embassy and then for Moravia in 863, and after Constantine's death at Rome in 869 the whole undertaking was his to carry alone.

The papacy backed it. He was consecrated archbishop with jurisdiction over Pannonia and Moravia, which revived an ancient see and also cut straight across territory the Bavarian bishops considered theirs. Their answer was direct. Around 870 he was seized, tried before a synod of Frankish bishops, and held in confinement in Bavaria for roughly three years, until Pope John VIII intervened, secured his release and instructed that the Slavonic liturgy be permitted.

He went back and kept working. The tradition credits him with translating most of the remaining books of the Bible into Slavonic in his last years, together with a collection of canon law for the new church. He died on 6 April 885, having named a successor. The Frankish party did not accept the succession, and within a short time his disciples were driven out of Moravia altogether.

What happened after 885 is the reason the work survived at all. The expelled disciples, among them Clement and Naum, went south into Bulgaria, where Prince Boris received them. There the Slavonic books were copied, schools were established at Preslav and at Ohrid, and the literature grew instead of stopping. Moravia itself reverted to a Latin church within a generation.

It is also where the alphabet changed. The script the brothers made was Glagolitic. The Cyrillic alphabet was developed in Bulgaria in the decades after 885, joining Greek uncial letters to signs for the Slavic sounds Greek had no letters for, several of those signs taken from Glagolitic. It is named for Cyril and he did not devise it, which makes the name a record of where the tradition begins rather than of who drew the letters.

Glagolitic did not simply vanish. It held on longest on the Adriatic coast, where an angular Croatian form stayed in liturgical use for centuries after it had gone everywhere else. Cyrillic travelled with Orthodox Christianity into Serbia, into the Rus and beyond, and its descendants are the everyday scripts of a great many languages now. Both brothers are venerated as saints in the Orthodox and Catholic churches and are named apostles of the Slavs.