"... and the Ecumenical Patriarch agreed to allow an autonomous Bulgarian Archbishop at Pliska. Missionaries from Constantinople, Cyril and Methodius..."
"... devised the Glagolitic alphabet, which was adopted in the Bulgarian Empire around 886.... In the early 9th century, a new alphabet — Cyrillic — was developed at the Preslav Literary School, adapted from the Glagolitic alphabet invented by Saints Cyril and Methodius...."
In Bulgaria, today's "History of" country.
In the following centuries Bulgaria established itself as a powerful empire, dominating the Balkans through its aggressive military traditions, which led to development of distinct ethnic identity. Its ethnically and culturally diverse people united under a common religion, language and alphabet which formed and preserved the Bulgarian national consciousness despite foreign invasions and influences.