Emperor Sizong of the Ming Dynasty, Zhu Youjian (1611-1644), was a younger brother of Emperor Xizong Zhu Youxiao and the last emperor of the Ming dynasty. He reigned for 17 years under the title of Chongzhen.

After his succession of the throne, Emperor Sizong was eager to salvage the dynasty. However, years of deep-rooted evils made it impossible to fundamentally improve the political situation in a short period. What's worse, he was self-opinionated, impetuous, skeptical and over anxious for quick success, so serious blunders were made repeatedly. And as a result, the defense at Liaodong almost collapsed at the critical time of the war against the Later Jin Dynasty. Then, Emperor Sizong increased taxes and dispatched more military forces to guard against the Later Jin Dynasty in the northeast and quell the peasant armies led by Li Zicheng and Zhang Xianzhong.

In 1644, the army led by Li Zicheng finally broke through defenses of the Ming Dynasty and occupied Beijing. Emperor Sizong hanged himself at the age of 34 and was buried in Siling.