In Bulgaria, Clement of Ohrid and Naum of Preslav created (or rather compiled) the new alphabet which was called Cyrillic and was declared the official alphabet in Bulgaria in 893. The Slavic language was declared as official in the same year. In the following centuries this alphabet was adopted by other Slavic peoples and states. The introduction of Slavic liturgy paralleled Boris' continued development of churches and monasteries throughout his realm.