[3] In the aftermath of Han-Zhao's capture of Emperor Huai during the Disaster of Yongjia in July 311, Su gathered a group of refugees on modern Shandong Peninsula and served as the leader of self-protection league.
Su became fearful, and in 319 he took his group of refugees south to join the Jin imperial regime under Emperor Yuan, then located at Jiankang.
He became proud of his success and began to have greater ambition, and he received criminals and other unwanted people into his commandery, seeking to strengthen his own personal force.
Su then declared a rebellion against Yu's regency, stating, in a famous quote: In other words, he would rather lose in battle and be executed, than to submit himself to what he thought was certain imprisonment.
He allied himself with Zu Yue the governor of Yu Province (豫州, usually referring to modern eastern Henan, but by that point mostly confined to central Anhui), and headed for Jiankang.
Su's forces pillaged the capital, stripping both officials and commoners of their wealths and even their clothing, and even the servant girls of Empress Dowager Yu, Emperor Cheng's mother, were seized.