868, however, the governor of Xusi Circuit, Cui Yanzeng (), ordered that the term be extended one year, causing the Xusi soldiers to mutiny under the leadership of Pang Xun. They headed northeast home, and when they reached Xusi's capital Xu Prefecture (), they attacked and captured it. After Pang's initial attempts to obtain an imperial commission was rebuffed, the mutineer army attacked the nearby regions, with the imperial forces unable to stop them. Not until Kang Chengxun, with major assistance from the Shatuo chieftain Zhuye Chixin (who was bestowed the imperial surname of Li, as well as a new name of Guochang because of his contributions), was able to defeat Pang in 869 was the rebellion suppressed. (Subsequently, though, Kang, due to the false accusations of the chancellor Lu Yan and the imperial scholar Wei Baoheng (the husband of Emperor Yizong's favorite daughter Princess Tongchang), was exiled.) Late reign Meanwhile, late in 869, Li Shiwang provoked Dali by killing its emissary Yang Qiuqing (). Dali's emperor Qiulong thus launched a major attack on Dingbian, and neither Li nor his successor Dou Pang () was able to repel it. The Dali forces quickly arrived at Chengdu's vicinity and put Chengdu under siege. Emperor Yizong commissioned Gao Pian as Xichuan's military governor, and Dali forces thereafter withdrew, but both Dingbian (which was then merged back into Xichuan) and Xichuan had been deeply wounded. Princess Tongchang died in 870, and this caused a major display of Emperor Yizong's caprice at the capital Chang'an, as Emperor Yizong, in anger that the imperial physicians were not able to cure her, executed some 20 imperial physicians and had some 300 of their relatives imprisoned. When the chancellor Liu Zhan and the mayor of Jingzhao Municipality (京兆, i.e., the Chang'an region) Wen Zhang () tried to intercede, both were exiled; in response, Wen committed suicide. Princess Tongchang was buried in a grand ceremony that demonstrated Emperor Yizong's wastefulness. As described in the Zizhi Tongjian: Despite Princess Tongchang's death, Emperor Yizong continued to remain close to Wei Baoheng, who became extremely powerful and corrupt late in Emperor Yizong's reign. Emperor Yizong also reacted in anger whenever Consort Guo's family was accused of misconduct. In 873, in a grand ceremony, Emperor Yizong welcomed what was claimed to be a relic (a finger bone) of Gautama Buddha to the palace, despite warnings by some that his grandfather Emperor Xianzong