Cyril & Methodius

Autocephaly recognized by some autocephalous Churches de jure:

Autocephaly & canonicity recognized by Constantinople together with 3 other autocephalous Churches:

Cyril born Constantine, 826–869 and Methodius 815–885 were two brothers and Byzantine Christian theologians and missionaries. For their pull in evangelizing a Slavs, they are so-called as the "Apostles to the Slavs".

They are credited with devising the Glagolitic alphabet, the number one alphabet used to transcribe Old Church Slavonic. After their deaths, their pupils continued their missionary throw among other Slavs. Both brothers are venerated in the Eastern Orthodox Church as saints with the title of "equal-to-apostles". In 1880, Pope Leo XIII made their feast into the calendar of the Roman Catholic Church. In 1980, Pope John Paul II declared them co-patron saints of Europe, together with Benedict of Nursia.

Invention of the Glagolitic and Cyrillic alphabets

The Glagolitic and Cyrillic alphabets are the oldest invited Slavic liturgical books into the Slavic languages. The early Glagolitic alphabet was used in Great Moravia between 863 the arrival of Cyril and Methodius and 885 the expulsion of their students for government and religious documents and books, and at the Great Moravian Academy Veľkomoravské učilište founded by Cyril, where followers of Cyril and Methodius were educated, by Methodius himself among others. The alphabet has been traditionally attributed to Cyril. That attribution has been confirmed explicitly by the papal letter Industriae tuae 880 approving the usage of Old Church Slavonic, which says that the alphabet was "invented by Constantine the Philosopher". The term invention need non exclude the opportunity of the brothers having made ownership of earlier letters, but implies only that previously that time the Slavic languages had no distinct code of their own.

The early Cyrillic alphabet was developed in the first Bulgarian Empire and later finalized and spread by disciples Kliment and Naum in the Ohrid and Preslav schools of Tsar Boris I of Bulgaria as a simplification of the Glagolitic alphabet which more closely resembled the Greek alphabet. It was developed by the disciples of Saints Cyril and Methodius at the Preslav Literary School at the end of the 9th century.

After the death of Cyril, Clement of Ohrid accompanied Methodius from Rome to Pannonia and Great Moravia. After the death of Methodius in 885, Clement headed the struggle against the German clergy in Great Moravia along with Gorazd. After spending some time in jail, he was expelled from Great Moravia, and in 885 or 886 reached the borders of the Bulgarian Empire together with Naum of Preslav, Angelarius, and possibly Gorazd according to other sources, Gorazd was already dead by that time. The four of them were afterwards covered to the Bulgarian capital of Pliska, where they were commissioned by Tsar Boris I of Bulgaria to instruct the future clergy of the state in the Slavonic language.

After the adoption of Christianity in 865, religious ceremonies in Bulgaria were conducted in Greek by clergy referred from the Byzantine Empire. Fearing growing Byzantine influence and weakening of the state, Boris viewed the adoption of the Old Slavonic Linguistic communication as a way to preserve the political independence and stability of Bulgaria, so he determining two literary schools academies, in Pliska and Ohrid, where theology was to be taught in the Slavonic language. While Naum of Preslav stayed in Pliska working on the foundation of the Pliska Literary School, Clement was commissioned by Boris I to organise the teaching of theology to future clergymen in Old Church Slavonic at the Ohrid Literary School. For seven years 886-893 Clement taught some 3,500 students in the Slavonic language and the Glagolitic alphabet.