Similar processes occurred in Southeast Europe with the Christianization of Bulgaria and the introduction liturgy in Old Bulgarian language and the Cyrillic script created in Bulgaria few years before the reign of Simeon I of Bulgaria, during the reign of his father Boris I of 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 Old Church Slavonic language was declared as official in the same year. In the following centuries the liturgy in Bulgarian language and the alphabet were adopted by many other Slavic peoples and counties. The Golden Age of medieval Bulgarian culture is the period of the Bulgarian cultural prosperity during the reign of emperor Simeon I the Great (889—927). The term was coined by Spiridon Palauzov in the mid 19th century. During this period there was an increase of literature, writing, arts, architecture and liturgical reforms.
