Emperor Wen died in 604—a death that traditional historians generally believe was a murder ordered by Yang Guang, although they admit a lack of direct evidence—and Yang Guang took the throne as Emperor Yang. In 605, he created Crown Princess Xiao empress. He soon turned away from the virtuous living style he engaged in to please his parents, and he lived luxuriously, with tens of thousands of women filling his palaces. He still maintained respect for Empress Xiao, and he made many of her relatives, including her older brother
Xiao Cong the Duke of Liang (Western Liang's final emperor), officials in his government. However, Yang Zhao, who became crown prince, died in 606, and Yang Shiku lost Emperor Yang's favor in 608 over his use of witchcraft against Yang Zhao's sons. Empress Xiao often accompanied Emperor Yang on his tours around the empire, and she saw that he had lost his virtues. She wrote a circumspect poem to try to get Emperor Yang to change his ways, but he either did not realize that was her intent, or simply ignored the poem. In 607, when Emperor Yang visited the submissive
Qimin Khan of the
Eastern Turkish Khaganate (
Tujue), Empress Xiao accompanied him and she personally visited the tent of the khan's wife Princess Yicheng, who was a daughter of a Yang clansman. In 615, when Emperor Yang and Empress Xiao were touring the northern frontier, Qimin Khan's son and successor
Shibi Khan launched a surprise attack against
Yanmen Commandery in reprisal against various offenses by the emperor. Princess Yicheng sent the imperial couple advanced warning of her new husband's plans, and they were able to reach the well-fortified commandery seat at present-day
Daixian in
Shanxi. When Shibi Khan besieged them there on 11 September, Empress Xiao's younger brother
Xiao Yu suggested seeking further assistance from Princess Yicheng, who—pursuant to Turkish custom—was entrusted with overseeing military affairs at home in her husband's absence. She sent the khan a false report of a northern attack on the khaganate; between this and reports of numerous Chinese reinforcements rushing to answer the emperor's call for help and extravagant promises of reward and promotion, the khan decided to lift the siege and return north. (Subsequently, though, rather than listening to Xiao Yu's advice to end his campaigns against
Goguryeo, Emperor Yang expelled the minister from his court.) By 618, with virtually entire empire engulfed in warfare from the rebellions against her husband's rule, Empress Xiao was with her husband at Jiangdu (), the capital of
Yang Province. They were protected (as he believed) by the elite Xiaoguo Army (). However, by this point, even the Xiaoguo soldiers were plotting rebellion, as they missed their families in the north. When a
lady in waiting reported the plot to Empress Xiao, she told the lady in waiting, "I will let you report it to the emperor." Emperor Yang, not willing to hear any bad news, however, instead executed the lady in waiting. Later, when other ladies in waiting wanted to report on the plot, Empress Xiao advised them against it, reasoning that there was nothing left that could save the dynasty. Soon, a plot led by the general
Yuwen Huaji came to fruition, and Emperor Yang, along with his sons Yang Shiku and Yang Gao and grandson Yang Tan the Prince of Yan were killed. Empress Xiao and her ladies in waiting wrapped him in a mat and made caskets for both Emperor Yang and Yang Gao. ==After Emperor Yang's death==