Asparuh’s Bulgars forced Byzantium to recognise a new empire
Between the seventh and eleventh centuries the First Bulgarian Empire dominated the northeastern Balkans. Asparuh’s Bulgars won Byzantine recognition around 680–681 to settle south of the Danube, and then spent the next several centuries as Constantinople’s chief northern rival, ally, and cultural counterpart.
Warfare never told the whole story: the two courts also cooperated, notably during the Second Arab siege of Constantinople. Inside the realm, Bulgar elites and other non-Slavic groups gradually adopted Slavic speech, forging a Bulgarian ethnonym that stuck in literature and daily talk from the tenth century onward.
Christianisation turned Bulgaria into Slavic Europe’s leading cultural workshop. Glagolitic arrived; Early Cyrillic was crafted at Preslav; Old Church Slavonic literature radiated outward. Under Simeon I in the late ninth and early tenth centuries, victories piled up, the ruler took the title tsar, and after destroying a Byzantine army at Anchialus in 917 Bulgarian forces even threatened Constantinople while borders peaked.
The Bulgars were Turkic-speaking, semi-nomadic warriors from the Pontic–Caspian steppe, first clearly recorded in 480 as allies of Emperor Zeno against the Ostrogoths. In the early 630s Kubrat, a khan from the Dulo clan, united the main tribes, threw off Avar rule and founded Old Great Bulgaria, stretching from the Azov and Black Sea shores to the Caucasus. Asparuh's band moved west into Bessarabia and the Danube Delta, crossing the river in the 670s; after Constantine IV failed against them, a Byzantine chronicler lamented that the emperor now paid tribute to these newcomers.
Modern historians call the state of 681 to 864 the Danube Bulgar Khanate, after its rulers' Turkic title. Christianisation came in 864 and Old Church Slavonic became the official language in 893; the ruler first took the title tsar in 913, and a fully independent Bulgarian Patriarchate followed in 927. Simeon's forces besieged Constantinople in 923 and 924 without success. Earlier, during the Second Arab Siege, a Bulgarian army had broken the blockade and destroyed the Arab force, sparing Southeastern Europe an invasion.
Source: First Bulgarian Empire
