Yabgu (literally, "pioneer", "guide") was a state office in the early
Turkic states, roughly equivalent to
viceroy. The title carried autonomy in different degrees, and its links with the central authority of
Kagan varied from economical and political subordination to superficial political deference.
The position of Yabgu was traditionally given to the second highest member of a ruling clan (Ashina), with the first member being the Kagan himself. Frequently, Yabgu was a younger brother of the ruling Kagan, or a representative of the next generation, called Shad (blood prince). Mahmud Kashgari defined the title Yabgu as "position two steps below Kagan", listing heir apparent Shad a step above Yabgu.[1].
As the centralized state disintegrated, the Yabgu was gaining more sovereignty, and historical records name a number of independent states with "Yabgu" being the title of the supreme ruler. One prominent example was the Oguz Yabgu state in Middle Asia, which was formed after the fragmentation of the Second Türkic Kaganate in the 840es. Another prominent example was the Karluk Yabgu, the head of the Karluk confederation which in the 766 occupied Suyab in the Jeti-su area, and eventually grew into a powerful Karakhanid state.[2]
Although believed by some to be a derivation from early Turkic davgu,[3] most scholars believe that that the word Yabgu is of Indo-European origin, and was perhaps borrowed by the Türks from the Kushan political tradition, preserved by the Hephtalites.[4] Peter B. Golden points out that there is also the possibility that the leaders of the Göktürk Empire, the Ashina, were themselves origianlly an Indo-European-speaking (possibly Iranian) clan who later adopted Turkic, but inherited their original Indo-European titles.[5] German Turkologist W.-E. Scharlipp writes that "a conspicuously large amount" of early Turkic titles are "in fact borrowings from Iranian", including "almost all of their titles".[6] Carter V. Findley also notes that "many elements of Non-Turkic origin became part of Türk statecraft [...] and [are] ever since in common use in Turkish,"[7] while explaning that the name Ashina itself "probably comes from one of the Iranian languages of Central Asia."[8] However, for the moment, the name yabgu defies any analysis as an Indo-European (compounded) form, whether it be Iranian or not.
