sentences:  Sipi was by then pronounced Zibil and he was a small khagan in charge of the western part of Tong Yabghu's empire, exactly as Ziebel was according to the Byzantine sources.Ziebel is described as the brother of Tong in the Byzantine sources, and as his uncle in the Chinese sources, a discrepancy which long precluded the identification.However uncle and elder brother is the same word in ancient Turkish, "äçi," and the Chinese sources could not render this double meaning with their very precise system of kinship names.