Old Great Bulgaria or
Great Bulgaria (
Byzantine Greek: Παλαιά Μεγάλη Βουλγαρία,
Palaiá Megálē Boulgaría) was a
Bulgar state known as
Patria Onoguria (Agathius, Priscus Rhetor, Zacharias Rhetor, and Pseudo-Zecharias Rhetor) and was а term used by Byzantine historians to refer to the initially Volga (before 463AD), then
Maeotian (before 7th century)
Bulgar state centred on
Phanagoria north of the
Caucasus mountains between the
Dniester and Lower
Volga. In the 6th century, after the defeat of Utigur Bulgars by Western Turks, it constituted the westernmost part of the
Turkic Khaganate. In the 7th century, during the reign of
Kubrat, it expanded west to include the lands of the
Avars while centered in
Poltava (modern
Ukraine) before the Kotharig Khan took control in the Volga-to-Caucasus region and subjugated Batbayan in Poltava. At the same time a new wave of Avars from Carpathia evicted Kubrat's governors south from
Sirmium while the
Battle of Ongal led to the establishment of a new Bulgarian state along the Danube under Kubrat's son
Asparukh.