who adapted the greek alphabet to the slavic languages
Early Cyrillic alphabet The Glagolitic alphabet was created by the monk Saint Cyril, possibly with the aid of his brother Saint Methodius, around 863.[8] Cyrillic, on the other hand, may have been a creation of Cyril's students (most notable of which was Clement of Ohrid) in the 890s at the Preslav Literary School under Bulgarian Tsar Simeon the Great as a more suitable script for church books, though retaining the original Bulgarian symbols in Glagolitic.[9] An alternative hypothesis proposes that it emerged in the border regions of Greek proselytization to the Slavs before it was codified and adapted by some systematizer among the Slavs; the oldest Cyrillic manuscripts look very similar to 9th and 10th century Greek uncial manuscripts,[8] and the majority of uncial Cyrillic letters were identical to their Greek uncial counterparts.[10] One possibility is that this systematization of Cyrillic was undertaken at the Council of Preslav in 893, when the Old Church Slavonic liturgy was adopted by the Bulgarian Empire.[10]