 As the National Revolutionary Army approached Beijing, Zhang Zuolin decided to retreat back to Manchuria, before he was assassinated by the Kwantung Army in 1928.His son, Zhang Xueliang, took over as the leader of the Fengtian clique in Manchuria.Later in the same year, Zhang decided to declare his allegiance to the Nationalist government in Nanjing under Chiang Kai-shek, and consequently, China was nominally reunified under one government.