Simeon I

Under Simeon I's patronage, the Preslav Literary School flourished, producing translations of Greek religious texts and original works in Old Church Slavonic. This cultural golden age advanced Slavic literature and liturgy.

Simeon I was crowned 'Emperor of the Bulgarians and the Romans' by the Patriarch of Constantinople, though the Byzantine court later disputed this. This act elevated Bulgaria to imperial status and challenged Byzantine supremacy.

Simeon I's Bulgarian army decisively defeated the Byzantine forces at the Achelous River. This victory allowed Simeon to claim the title 'Tsar of the Bulgarians and the Romans' and established Bulgaria as a major power in the Balkans.

Simeon I besieged Constantinople, the Byzantine capital, but failed to capture it. The siege ended with a peace treaty that recognized Simeon's imperial title but did not grant him control of the city.