Wu Sangui
On May27, as the Shun army approached the Shanhai Pass from the south, Wu Sangui opened the gates to let the Qing army through the pass from the north. Up to this point the Battle of Shanhai Pass between Li Zicheng and Wu Sangui had been moving in Li's favour, but the sudden appearance of the Manchu bannermen decisively routed the Shun forces. Having thus entered through the Great Wall, the Manchus seized Beijing on June5. They eventually defeated both the rebel-founded Shun dynasty and the remaining Ming resistance, establishing Qing rule over all of China.