Seizing opportunity, the Eight Banners crossed the Great Wall after the Ming border general Wu Sangui (1612–1678) opened the gates at Shanhai Pass. This occurred shortly after he learned about the fate of the capital and an army of Li Zicheng marching towards him; weighing his options of alliance, he decided to side with the Manchus. The Eight Banners under the Manchu Prince Dorgon (1612–1650) and Wu Sangui approached Beijing after the army sent by Li was destroyed at Shanhaiguan; the Prince of Shun's army fled the capital on the fourth of June. On 6 June, the Manchus and Wu entered the capital and proclaimed the young Shunzhi Emperor ruler of China. After being forced out of Xi'an by the Qing, chased along the Han River to Wuchang, and finally along the northern border of Jiangxi province, Li Zicheng died there in the summer of 1645, thus ending the Shun dynasty. One report says his death was a suicide; another states that he was beaten to death by peasants after he was caught stealing their food.