The early Cyrillic alphabet was developed in the First Bulgarian Empire[REF] and later finalized and spread by disciples Kliment and Naum in the Ohrid and Preslav schools of Tsar Boris' Bulgaria[REF] as a simplification of the Glagolitic alphabet which more closely resembled the Greek alphabet.
After the death of Cyril, Clement of Ohrid accompanied Methodius from Rome to Pannonia and Great Moravia.