First Bulgarian Empire
The First Bulgarian Empire was a medieval state that existed in Southeastern and southeastern Central Europe between the 7th and 11th centuries AD. It was founded in 680–681 after a group of Bulgars, led by Asparuh, moved south to the northeastern Balkans, and secured Byzantine recognition and their right to settle south of the Danube by defeating – possibly with the help of local South Slavic tribes – the Byzantine army led by Constantine IV. During the 9th and 10th century, Bulgaria reached the height of its power and stretched from the Danube Bend to the Black Sea and from the Dnieper River to the Adriatic Sea, becoming a major power capable of competing with the Byzantine Empire. As the state solidified its position in the Balkans, it entered into a centuries-long interaction, sometimes friendly and sometimes hostile, with the Byzantine Empire.