Xueyantuo (薛延陀), ethnic Shatuo

The Xueyantuo (薛延陀) (Seyanto, Se-yanto, Se-Yanto) or Syr-Tardush were an ancient Tiele Turkic people and Turkic khanate in central/northern Asia who were at one point vassals of the Gokturks, later aligning with China's Tang Dynasty against the Eastern Gokturks. Xueyantuo started from Selenga River/Xueyanhe River (薛延河江/偰輦河江), so tribe name is Seyanto/Xueyantuo (薛延陀), Chinese Han character undergo considerable revision by rise and fall of Chinese Dynasty, so have many name as Xueyantuo,Xueyanhe, Xienianhe, Seyanto, Selenga, Selyanha, etc.

On August 1, 646, they were defeated by the Uyghur (Huihu, 回纥) and the Chinese. The Xueyantuo's Duomi Khan, Bazhuo, was killed by the Uyghur. A Tang army led by the general Li Daozong, the Prince of Jiangxia crushed the Xueyantuo forces. The last Xueyantuo khan, the Yitewushi Khan Duomozhi, surrendered.^[8] For a (disputed) relationship with the later Shato Turks, see Shato. Their remnants were destroyed two years later, on September 15.

The Tang Huiyao also asserted that the rulers of Xueyantuo claimed to be originally named Xue (薛/偰), and that the name of the tribe was changed to Xueyantuo after the Xue defeated and merged the Yantuo into their tribe.^[15]

During the late Tang Dynasty, a group of Xueyantuo remnants known as Shatuo began to play a very important role in Chinese politics. Leaders of the following Jin Kingdom, theLater Tang, the Later Jin, the Later Han and the Northern Han state during the Five Dynasties and Ten Kingdoms were largely ethnic Shatuo.

The Uighurs who replaced the Turkic Empire referred to Turkic Empire as Turk-Kıvchak.^[2] in their monuments. Thus it seems that the names Sir and Kıvchak were used interchangeably and Kıvchak was the name Sir people assumed after the collapse of the Turkic Empire. The new name Kıvchak means "unfortunate" in Proto Turkic. This probably referred to the problems they encountered after the collapse of the empire. The remains of the Kıvchak people escaped to west to Kimek (or Yemek ) territory. TheKipchak people of the later era were undoubtedly the Kıvchak of the 8th century.