Taiwan was annexed by Japan in 1895 after the First Sino-Japanese War. In the Northern Expedition, the Nationalists defeated the warlords of the Beiyang clique and established a unified government for China in Nanjing. The United States recognised Republic of China (ROC) on 25 July 1928, the first government to do so. The Japanese occupied much of China during World War II. After Japan's defeat in 1945, Taiwan was placed under the temporary administration of the ROC to handle the surrender of Japanese administration. The Chinese Civil War broke out again between the Nationalists and the Communists. The Communists gained control of the mainland in 1949 and proclaimed the People's Republic of China (PRC), while the Nationalists fled to Taiwan, taking the ROC government with them. In 1952, Japan renounced Taiwan in the Treaty of San Francisco without specifying to whom Taiwan is ceded.