Emperor Taizong of Tang (r. 626-649), the second emperor of Chinese dynasty Tang Dynasty, faced a major threat from Tang's northern neighbor, the Eastern Turkic Khaganate, whom his father Emperor Gaozu of Tang had been subjugated by in several manners. Early in Emperor Taizong's reign, he placated the Eastern Turkic Khaganate's Jiali Khan Ashina Duobi, but, 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 it 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. After the destruction of the Eastern Turkic Khag