The Byzantine mission of saint brothers Cyril and Methodius had a major impact on the spiritual history of Great Moravia. In the centuries that followed, their works paved the way for the political and historical development of the Slavic nations, mainly in South-East and East Europe.
The mission, which reached Great Moravia in 863, had several dimensions. The most important were evangelism and the cultural and civilizational dimensions. Translations of the Gospel and liturgical texts into Old Church Slavonic intensified the religious life of our ancestors and laid the foundations of literature and culture for almost the entire Slavic world. From this point of view, research should be focused on the role and reflection of this historical and cultural heritage in the ecclesiastical and spiritual, national, and cultural life of the Slavic nations. The Cyrillo-Methodian idea manifests itself in the history of the Slavic world as a complex but solid foundation, capable of renewing the sleeping or inhibited energy and values in the areas of
faith, culture, literature, arts, education, upbringing, as well as national consciousness.

Most of the works on Cyril and Methodius are in Slavic or Russian. There are several helpful books in English, however. Francis Dvornik, The Slavs: Their Early History and Civilization (1956), describes the brothers’ influence on the life and language of the people among whom they worked. Zdenek Radslav Dittrich, Christianity in Great-Moravia (1962), is a scholarly study of the history of the churches they helped found, and Matthew Spinka, A History of Christianity in the Balkans (1968), places their missionary results in the context of the history of eastern Europe.