Ao, who set off from the Beidi Commandery (北地郡). Despite Gongsun Ao failing to keep up, Huo Qubing travelled over 2,000 li without backup, all the way past Juyan Lake to Qilian Mountains, killing over 30,000 Xiongnu soldiers and capturing a dozen Xiongnu princes. His march was then increased further by a 5,400 households for the victory. Huo Qubing's victories dealt heavy blows to the tribes of the Xiongnu princes of Hunxie () and Xiutu () that occupied the Hexi Corridor. Out of frustration, Yizhixie Chanyu wanted to mercilessly execute those two princes as punishment. The Prince of Hunxie contacted the Han government in autumn of 121 BC to negotiate a surrender. Failing to persuade his fellow prince to do the same, he killed the Prince of Xiutu and ordered Xiutu's forces to also surrender. When the two tribes went to meet the Han forces, Xiutu's forces rioted. Seeing the situation changed, Huo Qubing alone headed to the Xiongnu camp. There, the general ordered the Prince of Hunxie to calm his men and stand down before putting down 8,000 Xiongnu men who refused to disarm, effectively quelling the riot. The Hunxie tribe was then resettled into the Central Plain. The surrender of the Xiutu and Hunxie tribes stripped Xiongnu of any control over the Western Regions, depriving them of a large grazing area. As a result, Han Dynasty successfully opened up the Northern Silk Road, allowing direct trade access to Central Asia. This also provided a new supply of high-quality horse breeds from Central Asia, including the famed Ferghana horse (ancestors of the modern Akhal-Teke), further strengthening the Han army. Emperor Wu then reinforced this strategic asset by establishing five commanderies and constructing a length of fortified wall along the border of the Hexi Corridor. He colonised the area with 700,000 Chinese soldier-settlers. After the series of defeats by Wei Qing and Huo Qubing, Yizhixie Chanyu took Zhao Xin's advice and retreated with his tribes to the north of the Gobi Desert, hoping that the barren land would serve as a natural barrier against Han offensives. Emperor Wu however, was far from giving up, and planned a massive expeditionary campaign in 119 BC. Han forces were deployed in two separate columns, each consisting of 50,000 cavalry and over 100,000 infantry, with Wei Qing and Huo Qubing serving as the supreme commander for each. Emperor Wu, who had been distancing Wei