Preslav Literary School in the context of "Simeon I of Bulgaria"

The Golden Age of Bulgaria 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.

Simeon I achieved spectacular military and political successes, expanding Bulgarian territory and forcing the Byzantine Empire to recognise the imperial title of the Bulgarian monarchs. The capital Preslav was built in Byzantine fashion to rival Constantinople. Among the city's most remarkable edifices were the Round Church, also known as the Golden Church, and the imperial palace. At that time was created and painted Preslavian pottery, which followed the most prestigious Byzantine models. A chronicle of the 11th century testified that Simeon I had built Preslav for 28 years.

The Glagolitic script (/ˌɡlæɡəˈlɪtɪk/ GLAG-ə-LIT-ik, ⰳⰾⰰⰳⱁⰾⰻⱌⰰ, glagolitsa) is the oldest known Slavic alphabet. It is generally agreed that it was created in the 9th century for the purpose of translating liturgical texts into Old Church Slavonic by Saint Cyril, a monk from Thessalonica. He and his brother Saint Methodius were sent by the Byzantine Emperor Michael III in 863 to Great Moravia after an invitation from Rastislav of Moravia to spread Christianity there. After the deaths of Cyril and Methodius, their disciples were expelled from Moravia, and they moved to the First Bulgarian Empire instead. The Early Cyrillic alphabet, which was developed gradually in the Preslav Literary School by scribes who incorporated some Glagolitic letters when writing in the Greek alphabet, gradually replaced Glagolitic in that region. Glagolitic remained in use alongside the Latin script in the Kingdom of Croatia and alongside Cyrillic until the 14th century in the Second Bulgarian Empire and the Serbian Empire; in later periods, it was used mainly for cryptographic purposes.

Glagolitic also spread to the Kievan Rus' and the Kingdom of Bohemia. Although its use declined there in the 12th century, some manuscripts in the territory of the former retained Glagolitic inclusions for centuries. It had also spread to Duklja and Zachlumia in the Western Balkans, from where it reached the March of Verona. There, the Investiture Controversy afforded it refuge from the opposition of Latinizing prelates and allowed it to entrench itself in Istria, from which place it spread to nearby lands. It survived there and as far south as Dalmatia without interruption into the 20th century for Church Slavonic in addition to its use as a secular script in parts of its range, which at times extended into Bosnia, Slavonia, and Carniola, in addition to 14th–15th century exclaves in Prague and Kraków, and a 16th-century exclave in Putna.

The Early Cyrillic alphabet, also called classical Cyrillic or paleo-Cyrillic, is an alphabetic writing system that was developed in Bulgaria in the Preslav Literary School during the late 9th century. The systematization of Cyrillic may have been undertaken at the Council of Preslav in 893. It is used to write the Church Slavonic language, and was historically used for its ancestor, Old Church Slavonic.

It was also used for other languages, but between the 18th and 20th centuries was mostly replaced by the modern Cyrillic script, which is used for some Slavic languages (such as Russian), and for East European and Asian languages that have experienced a great amount of Russian cultural influence.

The Ohrid Literary School or Ohrid-Devol Literary school was one of the two major cultural centres of the First Bulgarian Empire, along with the Preslav Literary School (Pliska Literary School). The school was established in Ohrid (in what is now North Macedonia). Another center was Devol (modern-day Albania) as well as Drembica, Glavinica and Velika with unknown location. All the school centers were located in a then Bulgarian province known as Kutmichevitsa. It was founded in 886 by Saint Clement of Ohrid on the order of Boris I of Bulgaria simultaneously or shortly after the establishment of the Preslav Literary School. After Clement was ordained bishop of Drembica, Velika (bishopric) in 893, the position of head of the school was assumed by Naum of Preslav. The Ohrid Literary School used the Glagolitic alphabet from its establishment until the 12th century and Cyrillic from the end of the 9th century onward. Between 990 and 1015, Ohrid was the capital of the Bulgarian Empire and simultaneously also the seat of the Bulgarian Patriarchate.

The Bulgarian Cyrillic alphabet (Bulgarian: Българска кирилическа азбука) is used to write the Bulgarian language.The Cyrillic alphabet was originally developed in the First Bulgarian Empire during the 9th – 10th century AD at the Preslav Literary School.

It has been used in Bulgaria (with modifications and exclusion of certain archaic letters via spelling reforms) continuously since then, superseding the previously used Glagolitic alphabet, which was also invented and used there before the Cyrillic script overtook its use as a written script for the Bulgarian language. The Cyrillic alphabet was used in the then much bigger territory of Bulgaria (including most of today's Serbia), North Macedonia, Kosovo, Albania, Northern Greece (Macedonia region), Romania and Moldova, officially from 893. It was also transferred from Bulgaria and adopted by the East Slavic languages in Kievan Rus' and evolved into the Belarusian, Russian and Ukrainian alphabets and the alphabets of many other Slavic (and later non-Slavic) languages. Later, some Slavs modified it and added/excluded letters from it to better suit the needs of their own language varieties.