Complex sentence: Although Chen Jiongming and the Guangdong forces occupied Guangxi until April 1922, their occupation was largely nominal because armed bands of Guangxi loyalists began to gather under local commanders, calling themselves the Self-government Army.
Split into simpler sentences: Although Chen Jiongming and the Guangdong forces occupied Guangxi until April 1922, their occupation was largely nominal. Armed bands of Guangxi loyalists continued to gather under local commanders, calling themselves the Self-government Army.