Inner Mongolia used to be part of Greater Mongolia, until Mongolia became a part of China at 17th century following the Qing conquest. For three centuries, Mongolia was marked with little interests even during the expansion of Russian Empire. With the Qing collapse, China attempted to retake Mongolia only to see its rule fallen with the Mongolian Revolution of 1921, overthrowing the Chinese rule; but it was proposed that Zhang Zuoling's domain (the Chinese "Three Eastern Provinces") take Outer Mongolia under its administration by the Bogda Khan and Bodo in 1922 after pro-Soviet Mongolian Communists seized control of Outer Mongolia. However, China failed to take Outer Mongolia (which would become modern Mongolia) but successfully maintained their presence in Inner Mongolia. For this reason, it has led to a strong anti-Chinese sentiment among the native Mongol population in Inner Mongolia which have rejected assimilation, which prompted Mongolian nationalists and Neo-Nazi groups to be hostile against China. One of the most renown unrest in modern China is the 2011 Inner Mongolia unrest, following the murder of two ethnic Mongolians in separate incidents.