Ashina Helu
One of the most ambitious rulers of the dynasty was Emperor Taizong (r. 626-649). He initiated several significant war campaigns in Chinese history, most of them against powerful Turkic groups of Central Asia. This includes campaigns against Eastern Tujue, Tuyuhun, and the Xueyantuo. Armies were dispatched to invade the oasis states of the Tarim Basin. The kingdom of Karasahr was captured by Tang forces in 644 and the kingdom of Kucha was conquered in 649. The western expansion of the Tang Empire continued under Emperor Taizong's successor, Emperor Gaozong, who conquered the Western Turks in 657, led by the Turkic qaghan Ashina Helu, with an army under the command of General Su Dingfang.