section_path: History/Conversion of South and East Slavs
section_name: Conversion of South and East Slavs
paragraph_text: Conversion of South and East Slavs
  
  In the ninth and tenth centuries, Christianity made great inroads into pagan Europe, including Bulgaria (864) and later Kievan Rus' (988). This work was made possible by Cyril and Methodius of Thessaloniki, two brothers chosen by Byzantine emperor Michael III to fulfil the request of Rastislav of Moravia for teachers who could minister to the Moravians in their own language. Cyril and Methodius began translating the divine liturgy, other liturgical texts, and the Gospels along with some other scriptural texts into local languages; with time, as these translations were copied by speakers of other dialects, the hybrid literary language Church Slavonic was created. Originally sent to convert the Slavs of Great Moravia, Cyril and Methodius were forced to compete with Frankish missionaries from the Roman diocese; their disciples were driven out of Great Moravia in AD 886 and emigrated to Bulgaria.
  
  After the Christianisation of Bulgaria in 864, the disciples of Cyril and Methodius in Bulgaria, the most important being Clement of Ohrid and Naum of Preslav, were of great importance to the Orthodox faith in the First Bulgarian Empire. In a short time they managed to prepare and instruct the future Bulgarian clergy into the biblical texts and in AD 870 the Fourth Council of Constantinople granted the Bulgarians the oldest organised autocephalous Slavic Orthodox Church, which shortly thereafter became Patriarchate. The success of the conversion of the Bulgarians facilitated the conversion of the East Slavs. A major event in this effort was the development of the Cyrillic script in Bulgaria, at the Preslav Literary School in the ninth century; this script, along with the liturgical Old Church Slavonic, also called Old Bulgarian, was declared official in Bulgaria in 893.
  
  The work of Cyril and Methodius and their disciples had a major impact on the Serbs as well. They accepted Christianity collectively along familial and tribal lines, a gradual process that occurred between the seventh and ninth centuries. In commemoration of their baptisms, each Serbian family or tribe began to celebrate an exclusively Serbian custom called Slava (patron saint) in a special way to honour the saint on whose day they received the sacrament of baptism. It is the most solemn day of the year for all Serbs of the Orthodox faith and has played a role of vital importance in the history of the Serbian people. Slava remains a celebration of the conversion of the Serbian people, which the church blessed and proclaimed a church institution.
  
  The missionaries to the East and South Slavs had great success in part because they used the people's native language rather than Greek, the predominant language of the Byzantine Empire, or Latin, as the Roman priests did. Perhaps the greatest legacy of their efforts is the Russian Orthodox Church, which is the largest of the Orthodox churches.