Avar Khaganate

State · 561–805 CE · at its largest around 617 CE

A nomadic empire of the Pannonian Avars in the Carpathian Basin that raided Byzantium and besieged Constantinople in 626. Charlemagne's campaigns of the 790s broke its power.

On its lands while it lasted

Chufut-Kale (500–1490 CE): Capital of Crimean Khanate (1450–1490).
Devín (c. 623 CE): Capital of Samo's Empire (623–658).
Maria Saal (c. 661 CE): Capital of Carantania (661–749).
First Bulgarian Empire founded (681 CE): After defeating the Byzantines, Khan Asparukh founded the Bulgarian state south of the Danube, with its capital at Pliska.
Veliki Preslav (c. 682 CE): Capital of First Bulgarian Empire (682–1017).
Pliska (c. 682 CE): Capital of First Bulgarian Empire (682–1017).
Dubrovnik (700 CE): Capital of Republic of Ragusa (1385–1806).
Prague (800 CE): Capital of Duchy of Bohemia (896–1002), Kingdom of Bohemia (1202–1528), Holy Roman Empire (1346–1611), and 4 more.
Varangians to the Greeks (c. 800–1100 CE): Scandinavian traders and warriors travelled from the Baltic up the Neva and Volkhov past Novgorod, portaged to the Dnieper and sailed down past Kiev to the Black Sea and Constantinople.