IV. HUNS, 2nd Wave:
Great Khanate Bulgars (or Magna Bulgaria or Palaia Bulgaria): This was the first Bulgar state, formed by the union of the Kutrigers and Utigers in the Ukraine. It was broken up by the Khazar Turks around 670 AD. The remnants of the Great Khanate Bulgars went various ways:
Black (or Inner) Bulgars: These Bulgars remained in place as subjects of the conquering Khazar Turks.
Volga (or Silver) Bulgars: As Great Khanate refugees from the Khazar Turks they settled on the upper Volga River. They were pagans who converted to Islam in the early 900s AD. They established lucrative trade networks that competed with those of the Khazars during the 900s AD despite the fact that they were ostensibly vassals of the Khazars. They were attacked by Prince Sviatoslav I of the nascent Russian Kieven Rus' in 966 AD. After an inconclusive war between the Volga Bulgars and the Russians, they made peace with each other in 985 AD. They agreed that the Volga Bulgars would control trade along the Volga River (which lies to the east and flows into the Caspian Sea in the direction of Iran) while the Russians would control trade along the Dnieper River (which lies to the west and flows into the Black Sea in the direction of the Greek Christian Byzantine Empire). Nonetheless, there was intermittent warfare between the Volga Bulgars and the Russians over the following decades. The Volga Bulgars were wiped out by the Mongols of Ogedei Khan in 1236-1237 AD.
Danube Bulgars: As Great Khanate refugees from the Khazar Turks they settled on the lower Danube River around 679 AD. They conquered the indigenous Slavic population in the process. They made war on the Greek Christian Byzantine Empire with mixed results, ultimately losing in 813 AD when they failed to capture the Byzantine capital city of Constantinople:
Khanate Bulgars: They had emerged from the Danube Bulgars by 830 AD. They became Eastern Orthodox Christian in 864 AD. Around 898 AD, they lost the northern part of their lands to the invading Magyars. They were badly damaged by an attack by Prince Sviatoslav I of the nascent Russian Kieven Rus' in 967 AD. By about 1000 AD, they were absorbed into the settled indigenous Slavic population to form the basis of the modern country of Bulgaria.