Wallpaper for the Day of Bulgarian Enlightenment and Culture, celebrated on 24th of May, when is honoured the work of Saints Cyril and Methodius. The two brothers, born in Thessalonica in the 9th century, are developers of the Glagolitic alphabet (855), for translation of liturgical books from Greek into Slavonic, which influenced the cultural development of all Slavs. For theirs missionary work among the Slavic peoples of the Great Moravia and Pannonia, they were called 'Apostles to the Slavs'.