The Second Zhili–Fengtian War was a conflict between the Japanese-backed Fengtian clique based in Manchuria, and the more liberal Zhili clique controlling Beijing and backed by Anglo-American business interests. The war is considered the most significant in China's Warlord era, with the Beijing coup by Christian warlord Feng Yuxiang leading to the overall defeat of the Zhili clique. During the war the two cliques fought one large battle near Tianjin in October 1924, as well as a number of smaller skirmishes and sieges. Afterwards, both Feng and Zhang Zuolin, the latter being ruler of the Fengtian clique, appointed Duan Qirui as a figurehead prime minister. In south and central China, more liberal Chinese were dismayed by the Fengtian's advance and by the resulting power vacuum. A wave of protests followed. The war also distracted the northern warlords from the Soviet-backed Nationalists based in the southern province of Guangdong, allowing unhampered preparation for the Northern Expedition (1926–1928), which united China under the leadership of Chiang Kai-shek.