Ashina Helu
While the Turks were settled in the Ordos region (former territory of the Xiongnu), the Tang government took on the military policy of dominating the central steppe. Like the earlier Han dynasty, the Tang dynasty (along with Turkic allies) conquered and subdued Central Asia during the 640s and 650s. During Emperor Taizong's reign alone, large campaigns were launched against not only the Göktürks, but also separate campaigns against the Tuyuhun, the oasis city-states, and the Xueyantuo. Under Emperor Gaozong, a campaign led by the general Su Dingfang was launched against the Western Turks ruled by Ashina Helu.