Jiangling, permitting Western Liang a degree of self-governance. He also took Emperor Ming's daughter as the wife and princess to his son, Yang Guang the Prince of Jin. (After Emperor Ming's death in 585 and succession by his son Emperor Jing of Western Liang, however, Emperor Wen reestablished the post of commandant of Jiangling and again put Western Liang territory under military control.) By spring 583, the Göktürks' internal dissension had become serious enough that Emperor Wen felt comfortable enough to commission his brother Yang Shuang () the Prince of Wei to command a major attack against Ashina Shetu. Yang Shuang achieved a great victory, and part of his army, commanded by the general Yin Shou (), defeated Gao, forcing Gao to try to flee to the Qidan, but on the way, Gao was killed by his own subordinates, ending the last bit of Northern Qi resistance. After the defeat, the various subordinate khans further engaged in battles among themselves and against Ashina Shetu, with Sui watching by, refusing to give aid to any side. By 584, Ashina Shetu submitted to Sui, and even the resentful Princess Qianjin referred to Emperor Wen as "father." He created her the Princess Dayi. In summer 584, believing that the Wei River, on account of its sandbars and treacherous waters, was becoming too difficult of a route for food transport to Daxing, commissioned the official Yuwen Kai () to construct a canal between Daxing and Tong Pass, parallel to the Wei River, named the Guangtong Canal (), greatly easing the transport of food and other supplies to the capital region Guanzhong. Nevertheless, on account of a famine in Guanzhong in fall 584, Emperor Wen briefly took up residence in Luoyang. In 586, the officials Liang Shiyan () the Duke of Cheng, Yuwen Xin () the Duke of Qi, and Liu Fang the Duke of Shu—all three of whom were friends of Emperor Wen but all of whom believed that they had been slighted by Emperor Wen—were accused of plotting rebellion, and all three were executed. In spring 587, continuing his canal-building regime, Emperor Wen built the Shanyang Canal () between the Yangtze River and the Huai River to improve the transport of material between those two rivers. In fall 587, Emperor Wen summoned Western Liang's Emperor Jing to Chang'an to meet him. Emperor Jing complied with the direction. While Emperor Jing was away, however,