In the hierarchy of the Gokturk and Khazar empires, an Elteber was the client-king of an autonomous but tributary tribe or polity. The Gokturks or Kokturks (Gök-Turks or Kök-Turks, with the meaning Celestial Turks), known as Tujue (突厥 tu2 jue2) in medieval Chinese sources, established the first known Turkic state around 552 under the leadership of Bumin/Tuman Khan/Khaghan (died 552) and his sons, and expanded rapidly to rule... The Khazars were a Turkic semi-nomadic people from Central Asia who adopted Judaism. ...

In the case of the Khazar Khaganate, the rulers of such vassal peoples as the Volga Bulgars, Burtas, and North Caucasian Huns were called elteber or some variant such as Ilutwer, Yiltawar, or Ilutver. A vassal, in European medieval feudalism terminology, is one who through a commendation ceremony (composed of homage and fealty) enters into mutual obligations with a lord, usually military conscription and mutual protection, in exchange for a fief. ... Bulgaria, known today as Volga Bulgaria, is a historic state that existed between the 7th and 13th centuries around the confluence of the Volga and Kama Rivers in what is now the Russian Federation. ... Burtas or Bortas (plural Bortaslar) were a tribe of uncertain ethnolinguistic affiliation inhabiting the steppe region north of the Caspian in medieval times. ... A branch of the Huns that established a polity in Daghestan and parts of Azerbaijan in the 500s and 600s CE. The North Caucasian Huns probably incorporated numerous indigenous Caucasian tribes following their settlement in the area. ...