Yan forces have captured Chang'an by early…

Yan forces have captured Chang'an by early 757 and forced both Emperor Xuanzong and his crown prince Li Heng to flee.

It is said that An Lushan was having eye problems and had become blind, and was also suffering from ulcers on his body.

As a result, his temper has become terrible, and his servants, if they have caused him any ill will, are often whipped or caned, and sometimes even executed.

Having declared imperial title, he spends most of his time inside the Luoyang palace, and his generals rarely see him, with most important matters going through his official Yan Zhuang,—but even Yan and a favorite eunuch of An's, Li Zhu'er, are being frequently battered.

Meanwhile, An Lushan favors another son An Qing'en, the son of his second wife Lady Duan (who might have carried the title of empress by this point).

An considers naming An Qing'en as his crown prince, instead of An Qingxu, who is otherwise considered to have received this honor.

An Qingxu often fears that An Lushan will put him to death.

He, Yan, and Li Zhu'er therefore plot.

On the night of January 29, 757, with Yan and An Qingxu watching outside, Li Zhu'er takes a sword into the palace and attacks An Lushan; An Lushan tries to fight back, but cannot locate a sword that he had put under his bed, and LI Zhu'er kills him.

The next morning, Yan first announces to the Yan officials that An Lushan is seriously ill and is creating An Qingxu crown prince.

An Qingxu then takes the throne before announcing An Lushan's death.