Modern history:

The May Fourth Movement helped to rekindle the then-fading cause of republican revolution. In 1917 Sun Yat-sen had become commander-in-chief of a rival military government in Guangzhou in collaboration with southern warlords. Sun's efforts to obtain aid from the Western democracies were ignored, however, and in 1920 he turned to the Soviet Union, which had recently achieved its own revolution. The Soviets sought to befriend the Chinese revolutionists by offering scathing attacks on Western imperialism. But for political expediency, the Soviet leadership initiated a dual policy of support for both Sun and the newly established Chinese Communist Party (CCP).

Please answer a question about this article. If the question is unanswerable, say "unanswerable". Sun Yat-Sen became the leader of what military group.
a rival military government in Guangzhou