In summer 762, Emperor Xuanzong died. Emperor Suzong was bedridden by this point, and it was said that he was so saddened by Emperor Xuanzong's death that his illness further advanced. He thus granted regent powers on Li Yu. By this point, Empress Zhang and Li Fuguo were no longer allies, and Empress Zhang summoned Li Yu, wanting an alliance with him to kill Li Fuguo and his subordinate Cheng Yuanzhen. Li Yu refused, pointing out that this would cause alarm to the very-ill Emperor Suzong. Empress Zhang then entered into an alliance with Li Yu's younger brother Li Xi () the Prince of Yue, and they tried to set a trap for Li Fuguo, with 200 strong eunuchs loyal to her and Li Xi ready to act against Li Fuguo. On May 14, 762, she issued an order in Emperor Suzong's name, summoning Li Yu into the palace. However, Cheng received this news and reported this to Li Fuguo and Li Yu, and Cheng then escorted Li Yu to the imperial guard headquarters. Imperial guards commanded by Li Fuguo and Cheng then entered the palace and arrested Empress Zhang, Li Xi, and their associates. It was said that with Emperor Suzong resting at Changsheng Hall (), the soldiers dragged Empress Zhang and the attending ladies in waiting and eunuchs away from his presence. Emperor Suzong was said to be left alone without attendants. He died on May 16, only 13 days after Emperor Xuanzong's death. Li Fuguo executed Empress Zhang, Li Xi, and Li Xian () the Prince of Yan and then declared Li Yu emperor (as Emperor Daizong).