The Kabars rebelled against the Khazar Khaganate in the early ninth century; the rebellion was notable enough to be described in Constantine Porphyrogenitus's work De Administrando Imperio. Subsequently the Kabars were expelled from the Khazar Khaganate and sought refuge by joining the Rus' people and the Magyar tribal confederacy called Hét-Magyar (meaning "seven Hungarians"). According to Magocsi, "A violent civil war took place during the 820s [...] The losers of the internal political struggle, known as Kabars, fled northward to the Varangian Rus' in the upper Volga region, near Rostov, and southward to the Magyars, who formerly had been loyal vassals of the Khazars. The presence of Kabar political refugees from Khazaria among the Varangian traders in Rostov helped to raise the latter's prestige, with the consequence that by the 830s a new power center known as the Rus' Kaganate had come into existence." Kabars or Cowari certainly also assisted in the Magyar invasion of Pannonia and the subsequent formation of the Principality of Hungary in the late 9th century.
Around 833 the Hungarian tribal confederacy was living in Levedia, between the Don and the Dnieper rivers, within the orbit of the Khazar empire. Toward 850 or 860, driven from Levedia by the Pechenegs, they entered Atelkuzu (Etelköz). The Magyars reached the Danube river basin around 880.
The origin of the name Hungary is believed to originate from the Bulgar tribal confederacy named On-Ogur, (meaning "ten" Ogurs) (comparable to Tokuz-Oguz (meaning "nine" Oguz)), who ruled the territory of Hungary prior to the arrival of the Magyars.
Many Kabars settled in the Bihar region of the later Kingdom of Hungary and Transylvania now in Romania. Some historians believe the character recorded by Gesta Hungarorum as lord Marot and his grandson Menumorut, dux of Biharia, were of Kabar descent. The tribe of Kubrat's Dulo clan was called Kubiar. The miracles of Saint Demitrius mentions the migration of a Kubar tribe from Syrmia to Macedonia in the 670s and one of the names on the Kievian Letter is "Kiabar", which may suggest that Kabars settled in Kiev as well. At least some Kabars were of Jewish faith; others may have been Christians, Muslims or shamanists.
Bunardžić dated Avar-Bulgar graves excavated in Čelarevo, containing skulls with Mongolian features and Judaic symbols, to the late 8th and 9th centuries. Erdely and Vilkhnovich consider the graves to belong to the Kabars who eventually broke ties with the Khazar Empire between the 830s and 862.
In 894, the Byzantine emperor Leo VI, then at war with Simeon, the Bulgarian czar (893–927), called the Hungarians to his aid. The Magyars, led by Árpád, crossed the Danube and attacked Bulgaria. The Bulgarians, in turn, appealed to the Pechenegs, now masters of the steppe, who attacked the Hungarians in the rear and forced them to take refuge in the mountains of Transylvania. At that moment, Arnulf, duke of Carinthia, at war with the Slav ruler Svatopluk, prince of Great Moravia (885–894), decided like the Byzantines to appeal to the Hungarians. The Hungarians overcame Svatopluk, who disappeared in the conflict (895). Great Moravia collapsed, and the Hungarians took up permanent abode in Hungary (907).
The presence of a Turkic aristocracy among the Hungarians could explain the Byzantine protocol by which, in the exchange of ambassadors under Constantine Porphyrogenitus, Hungarian rulers were always referred to as "Princes of the Turks".
The Kabars supposedly left scattered remains and some cultural and linguistic imprints, but this is debatable.
A Kabar inscription
The Mihai Viteazu inscription (Alsószentmihály inscription), discovered in the 20th century in present-day Romania, is one of few surviving relics of the Kabars. It was transcribed by the archaeologist-historian Gábor Vékony. According to the transcription, the meaning of the two-row inscription is the following: (first row) "His mansion is famous." and (second row) "Jüedi Kür Karaite." or "Jüedi Kür the Karaite." See more details: Inscription in Khazarian Rovas script and RovasPedia.
- Róna-Tas, András (1996): A honfoglaló magyar nép. Bevezetés a korai magyar történelem ismeretébe [The conquering Hungarian nation. Introduction to the knowledge of the early Hungarian history]. Budapest: Balassi Kiadó, ISBN 963-506-106-4
- Khavars in the Rovaspedia
- According to the Turcologist András Róna-Tas, the name Kabar" is faulty, the right pronunciation is Khavar. Róna-Tas, András (1996a): A honfoglaló magyar nép. Bevezetés a korai magyar történelem ismeretébe [The conquering Hungarian nation. Introduction to the knowledge of the early Hungarian history]. Budapest: Balassi Kiadó, p. 273
- ""A violent civil war took place during the 820s [...] The losers of the internal political struggle, known as Kabars, fled northward to the Varangian Rus' in the upper Volga region, near Rostov, and southward to the Magyars, who formerly had been loyal vassals of the Khazars. The presence of Kabar political refugees from Khazaria among the Varangian traders in Rostov helped to raise the latter's prestige, with the consequence that by the 830s a new power center known as the Rus' Kaganate had come into existence."Magocsi, Paul Robert (2010). A History of Ukraine: A Land and Its Peoples. Toronto: University of Toronto Press. p. 62.
- Peter F. Sugar, Péter Hanák, Tibor Frank, A History of Hungary, Indiana University Press, 1994 page 11.
- Golden, Peter B. "The Conversion of the Khazars to Judaism." The World of the Khazars: New Perspectives. Brill, 2007. p. 150.
- René Grousset, The Empire of the Steppes, p.178. Rutgers University Press, 1988. ISBN 0-8135-1304-9
- Vékony, Gábor (2004): A székely rovásírás emlékei, kapcsolatai, története [The Relics, Relations and the History of the Szekely Rovas Script]. Publisher: Nap Kiadó, Budapest. ISBN 963-9402-45-1
- Vékony, Gábor (1997): Szkíthiától Hungáriáig: válogatott tanulmányok. [From Scythia to Hungary: selected Studies] Szombathely: Életünk Szerk. Magyar Írók Szövetsége. Nyugat-magyarországi Csoport. Ser.: Életünk könyvek, p. 110