Her father, whose personal name was Aguzhi (阿古只) and who was probably still using the surname Shulü (述律) at the time that she was born, was a younger brother of Empress Shulü Ping, the wife of Liao's founder Emperor Taizu.
[3] (Xiao Sagezhi's cousin Xiao Han was described by the Song dynasty historian Sima Guang, in his Zizhi Tongjian, as the first member of the Shulü household to use the name of Xiao, although it is not clear whether Sima's assertion was actually correct;[4] the History of Liao explained that because Emperor Taizu admired the Han dynasty founder Emperor Gao, he had his own Yelü clan take on the Han Chinese surname of Liu, while having the clans of past and present consorts of Yelü chieftains take on the surname of Xiao, after Emperor Gao's prime minister Xiao He; based on Liao tradition, nearly all of the subsequent empresses of Liao carried the name of Xiao.
)[3] During the time that Yelü Ruan was carrying the title of Prince of Yongkang under his uncle Emperor Taizong—part of the year of 947[1]—he took Xiao Sagezhi as a consort.
[3] (As Yelü Ruan was a grandson of Emperor Taizu's, they were first cousins, once removed.
[7] In 950, for reasons unclear in history, Emperor Shizong created Xiao Sagezhi empress,[1] even though he had already earlier created Lady Zhen (the mother of his third son, Yelü Zhimo (耶律只沒)), as empress.