Su Dingfang
In late 629, believing the time ripe for a major attack on the Eastern Turks, Emperor Taizong commissioned the general Li Jing with overall command of a multi-pronged army, assisted by the generals Li Shiji, Li Daozong, Chai Shao, Xue Wanche (, Xue Wanjun's brother) and Su Dingfang, attacking the Eastern Turks at multiple points. The army was successful in its attacks, forcing Ashina Duobi to flee, and by late spring 630, Ashina Duobi had been captured, and Eastern-Turkish chieftains all submitted to Tang. Emperor Taizong spared Ashina Duobi but detained him at Chang'an, and he considered what to do with the Eastern Turks.