Saints Cyril and Methodius are equally revered by both the Catholic and the Orthodox Churches. In the Russian Orthodox Church, the memory of the equal-to-apostles enlighteners of the Slavs has been celebrated since the 11th century. The oldest services to the saints that have reached our time date back to the 13th century.
Cyril and Methodius carried out the translations of the Holy Scripture books from Greek into Slavic, as well as some other literature necessary for worship. They created a special alphabet for the texts of the translations - Glagolitic script. As a result of the translation activities of Cyril and Methodius, a literary language of as high a level as Greek and Latin was created.