A long time ago, a Taoist had spoken to Empress Zhangxian words of a prophecy. At the time, Empress Zhangxian was still just Consort Liu. The Taoist said that she will have no children of her own but because of this; she was worried about her position. Without a child of her own, she could never climb higher to become the Empress.
Consort Liu knew Lady Li had caught the eyes of Emperor Zhenzong. The Emperor who had fallen in love with Lady Li, a servant of Consort Liu at the time. Consort Liu had created an opportunity for Emperor Zhenzong to sleep with Lady Li in her own chamber.
That night, Lady Li became pregnant. But that same night, Emperor Zhenzong had promised Lady Li that when morning comes, he will promote her to Guifei. Consort Liu heard their conversation and became furious.