Gushu City was first built during the Huangwu era of Eastern Wu and took its name from Gushu Creek. With Baizhu Mountain to the east and the Yangtze River to the west, it was the gateway to Jiankang. Whoever controlled Gushu City held Jiankang's gates wide open.
During Emperor Yuan of Jin's reign, Wang Dun, the Grand General Who Guards the East, raised a rebellion in the name of "clearing evil ministers from the emperor's side." He marched into Jiankang, killed his opponents, and returned to garrison Wuchang. After Emperor Ming of Jin ascended the throne, he was forced to summon Wang Dun to court to assist with government affairs. Wang Dun moved his headquarters from Wuchang to Gushu, appointed himself Governor of Yangzhou, and controlled Jiankang from afar. Had age and illness not left him powerless to act, the Jin Dynasty's Mandate would already have ended.
Huan Wen had always admired Wang Dun. Passing Wang Dun's tomb, he called him an admirable fellow-someone who pleased him in every way. That Huan Wen so admired a rebellious minister revealed his own disloyal intentions. During the Shengping era, he followed Wang Dun's example and moved his headquarters from Jingzhou to Gushu under the pretext of a Northern Expedition. His desire to usurp the throne was known to every passerby. The Jin imperial house and the Wang and Xie great families had to rely on Huan Wen to resist the Fu clan's Qin and the Murong clan's Yan in the north, yet also feared his usurpation. With no effective means of checking him, they could only watch helplessly as his power grew-
Huan Wen resembled Wang Dun in another respect: Wang Dun had married Emperor Wu of Jin Sima Yan's daughter, the Princess of Xiangcheng, while Huan Wen's wife was Emperor Ming