Simeon (also Symeon) I the Great rules over Bulgaria from 893 to 927, during the First Bulgarian Empire.

Simeon's successful campaigns against the Byzantines, Magyars and Serbs lead Bulgaria to its greatest territorial expansion ever, making it the most powerful state in contemporary Eastern Europe.

His reign is also a period of unmatched cultural prosperity and enlightenment later deemed the Golden Age of Bulgarian culture.

During Simeon's rule, Bulgaria spreads over a territory between the Aegean, the Adriatic and the Black Sea, and the new Bulgarian capital Preslav is said to rival Constantinople.

The newly independent Bulgarian Orthodox Church becomes the first new patriarchate besides the Pentarchy, and Bulgarian Glagolitic translations of Christian texts spread all over the Slavic world of the time.

Halfway through his reign, Simeon assumes the title of Emperor (Tsar), having prior to that been styled Prince (Knyaz).