Complex sentence: The pro-Soviet leader Sheng Shicai of Xinjiang province in China launched his own purge in 1937 to coincide with Stalin's Great Purge, the Xinjiang War (1937) broke out amid the purge.
Split into simpler sentences: The pro-Soviet leader Sheng Shicai of Xinjiang province in China launched his own purge in 1937 to coincide with Stalin's Great Purge. The Xinjiang War (1937) broke out amid the purge.