"The idea that a Shad left behind in the Caucasus might have played an important role in the birth of the Khazar Empire is an old one. We still do not have the slightest positive proof of this, but the Ziebel-Sipi identification certainly supports the assumption that this Shad and the right wing of the Turkic army stayed behind and never came back to Central Asia. The Ashinas-like rituals of the Khazar kings should be explained in one way or another, and I would quite agree with the idea that the Khazar Empire was born of the mixing of these Turkic tribes under Ashinas leadership and the Khazars coming from the Middle Volga, one generation after the siege of Tiflis."

http://www.academia.edu/7248381/Ziebel_Qaghan_identified