Eastern half of the split First Turkic Khaganate, dominant in Mongolia until subjugated by Tang China in 630.
Conquered by Tang China in 630 CE when General Li Jing defeated Illig Qaghan at the Battle of Yinshan (27 March 630), and the khagan was captured on 2 May 630 and taken prisoner to Chang'an, ending the Eastern Turkic Khaganate.
Classic survey of steppe empires covering the Turkic khaganates including the Eastern branch; Rutgers University Press, confirmed via Cambridge Core and Rutgers UP catalogue.