Overview
Consort Xiao, Pure Consort Xiao or Xiao Shufei (蕭淑妃, personal name unknown) (died after 16 November-3 December 655), was a concubine of Emperor Gaozong of Tang (Li Zhi). She was initially favored by him and bore him a son and two daughters—Li Sujie and the Princesses Yiyang and Gao'an—but later, after her romantic rival Empress Wang introduced another concubine, Consort Wu (later known as Wu Zetian), to Emperor Gaozong, Emperor Gaozong became enamored with Consort Wu. Empress Wang and Consort Xiao instead joined forces to try to counter Consort Wu, but in 655, Emperor Gaozong deposed both of them on accusations of witchcraft and replaced Empress Wang with Consort Wu. Soon, they were executed on the new Empress Wu's orders.
Background
Little is known about Consort Xiao's background. What is known is that she was already a concubine of Li Zhi when he was crown prince under his father Emperor Taizong, as her son Li Sujie was born in 645, before his ascension in 649. While she was a concubine to the crown prince, she carried the title of Liangdi (良娣). In addition to Li Sujie, she bore two daughters, who were probably older than Li Sujie. It was also said that she was favored by him, more so than his wife Crown Princess Wang.
As imperial consort
In 649, after Emperor Taizong died, Li Zhi took the throne (as Emperor Gaozong). He created Crown Princess Wang empress, and he created Consort Xiao the rank of Shufei, the second highest rank for imperial concubines. She continued to be favored, which drew jealousy from Empress Wang, and Empress Wang's jealousy soon caused both of them to face a different romantic rival.
When Emperor Gaozong was crown prince, he had been attracted by the beauty of one of Emperor Taizong's concubines, Consort Wu. After Emperor Taizong's death, all of his concubines who did not bear sons were housed at Ganye Temple (感業寺) to be Buddhist nuns. In either 650 or 651, when Emperor Gaozong was visiting Ganye Temple to offer incense to Buddha, when he saw Consort Wu. Both of them wept. When Empress Wang heard this, she, wanting to divert Emperor Gaozong's favor from Consort Xiao, secretly instructed Consort Wu to grow her hair back, while suggesting to Emperor Gaozong that he take her as a concubine.
From Wikipedia (CC BY-SA 4.0).