Emperor Taizong of Tang (r. 626-649), the second emperor of Chinese Tang Dynasty, faced a major threat from Tang's northern neighbor, the Eastern Turkic Khaganate. Early in Emperor Taizong's reign, he placated the Eastern Turkic Khaganate's Illig Qaghan (also called Jieli Khan and Ashina Duobi), while preparing for several years for a major offensive against the Eastern Turkic (including forming an alliance with the Eastern Turkic Khaganate's restless vassal Xueyantuo, which was ready to throw off the Eastern Turkic yoke). He launched the offensive in winter 629, with the major general Li Jing in command, and in 630, after Li Jing captured Ashina Duobi, the Eastern Turkic Khaganate was destroyed. Subsequently, control of the territory north of Tang (check mate ak.w.m) largely fell to Xueyantuo, and Emperor Taizong initially tried to settle many the Eastern Turkic people within Tang borders. Eventually, after an incident where he was nearly assassinated by a member of the Eastern Turkic royal house, Ashina Jiesheshuai, he tried to resettle the Eastern Turkic people north of the Great Wall and south of the Gobi Desert, to serve as a buffer between Tang and Xueyantuo, creating a loyal Eastern Turkic Khaganate's prince Ashina Simo as the Qilibi Khan, but Ashina Simo's reign collapsed around new Year 645 due to dissent within and pressure from Xueyantuo without, and Tang would not attempt to recreate the Eastern Turkic Khaganate any further (although remnant tribes rose later, and during the reign of Emperor Taizong's son Emperor Gaozong, Eastern Turkic was reestablished under Ashina Gudulu, as a hostile power against Tang).