Zhang Zuolin (1875-1928), known as 'the Old Marshal', was perhaps the most powerful individual warlord in China during the 'Warlord Era' of 1916-1928. He began his adult life as a bandit in Manchuria), but his forces were absorbed into the Chinese Army and in time he was appointed governor-general of the three provinces of Heilongjiang, Jilin and Liaoning. He built up substantial armed forces and his small air force carried out the first air raids in Chinese history. He was supported by Japan, which had large garrisons and economic interests in Manchuria; Japanese aid helped him to survive and defeat a rebellion by a subordinate general, Guo Songling, in 1925. Zhang was able to dominate the official national government, in Beijing, in the periods 1924-25, and again 1925-1928. However, in 1928 he was driven out of Beijing by the warlord Yan Xishan who had expressed loyalty to Chiang Kai-shek. Returning to his Manchurian base, he was assassinated (through the act of blowing up his train) by his former Japanese patrons, having lost his usefulness to them. He was replaced in power in the north-east by his son Zhang Xueliang (Chang Hsueh-liang) (1900-2001).