After the Mukden Incident of September 18, 1931, the Japanese Kwantung Army invaded Manchuria, and by February 1932 had captured the entire region. The last emperor of the Qing Dynasty, Puyi, who was living in exile in Tianjin was invited by the Japanese to accept the throne of the new Empire of Manchukuo, which was controlled by the Japanese army. In January 1933, to guard Manchukuo’s southern borders, a joint Japanese and Manchukuo force invaded Rehe, and after conquering that province by March, drove the remaining Chinese armies in the northeast outside the Great Wall into Hebei Province.