The Kengeres, mentioned in the Orkhon inscriptions, were possibly known in the Islamic world and in the west as Kangar, a collective name for three Pecheneg tribes. Byzantine emperorConstantine Porphyrogenitus stated that Kangar signified nobleness and bravery. Ukrainian historian Omeljan Pritsak suggested that Kangar originated from Tocharian A *kânk "stone" and Kengeres combined Kenger with the Iranian ethnonym As, supposedly from *ârs < *âvrs < *Aoruša . However, Golden objected that *Aoruša would have yielded Ors/Urs and Pritsak's opinion on the Kengeres-Kangars' ethnonym and mixed Tocharian-Iranian origin remained "highly hypothetical". Other Orientalists, Marquart, Toltsov, :ru:Кляшторный, Сергей Григорьевич|Klyashtorny, attempted to connect the Kangar and Kengeres to the Qanglı, the eastern grouping of the Cuman-Kipchak confederation as well as the Indo-European Kangju in Chinese sources. Akhinžanov proposed that the Kipchaks simply assumed the name Qanglı after taking over the Kang region. Nevertheless, all of these connections, if any, remain unclear.
Independence
After the capture of Zhetysu by the Chinese, Kangars become independent from the Turkic Kaganate. The Syr Darya cities retained their autonomy. The Oguzes in the southern Kazakhstan, Kimaks in the Irtysh River valley, Cumans in Mugodjar, and Kypchaks in the northern Kazakhstan became the vassals of the Kangar union. At the end of the 7th century the Syr Darya cities rebelled and formed an alliance with the Sogdiana. The revolt was successful, but the Moslem Arab armies attacked Sogdiana from the south. The revolt has waned, and Kangars consented to the continued autonomy of the Syr Darya cities.
At the beginning of the 8th century the Oghuz confederation and the city ofTashkent seceded from the Kangar union. The Arabs continued raiding Sygnakh, Jend, and other rich Kangar cities. The Oguzes formed an alliance with the Kimaks and Karluks, and their joint assault defeated the Kangars, whose union dissolved. Three Kangar tribes and five allied Turkic tribes, under the collective name Pecheneg, later carved out a realm, which bordered both the Ouzes and the Khazars, in Eastern Europe.