The "golden age" of that state of this people occurred after Byzantine general Leo Phocas was defeated at the Battle of (*) Achelous by an emperor of this people named Simeon I. A leader of this people named Samuel was defeated at the Battle of Kleidion, whose victor was given an epithet signifying his conquest of this people.
A man from the Utigur branch of this people named Kubrat or Kurt was the founder of an "old great" confederation of them north of the Caucasus. Another member of this people, Asparukh, won the 688 CE Battle of Ongal over Constantine IV, thus becoming the founder of a state of this people that had a major cultural center at Preslav. The "golden age" of that state of this people occurred after Byzantine general Leo Phocas was defeated at the Battle of (*) Achelous by an emperor of this people named Simeon I. A leader of this people named Samuel was defeated at the Battle of Kleidion, whose victor was given an epithet signifying his conquest of this people. For 10 points, name this ethnic group whose members Byzantine emperor Basil II was known as the "slayer" of.
A man from the Utigur branch of this people named Kubrat or Kurt was the founder of an "old great" confederation of them north of the Caucasus.
Bulgars [accept Bulgarians]