《旧唐书·本纪·卷十一》
宝应元年四月，肃宗病危，肃宗所宠信的张皇后没有儿子，张皇后害怕李豫功劳大难以控制，暗中将越王亻系带入宫中，将图谋废除太子李豫。
宝应元年四月，肃宗大渐，所幸张皇后无子，后惧上功高难制，阴引越王系于宫中，将图废立。
In April of the first year of the Baoying era, Emperor Suzong was critically ill. Emperor Suzong's favourite concubine, Empress Zhang, had no son. Empress Zhang was afraid that Li Yu would be difficult to control if he had great merit, so she secretly brought the King of Yue, Ren Xi, into the palace and plotted to abolish the Crown Prince Li Yu.