In 327, apprehensive of Su's ambitions, Yu became intent on stripping him of his military command, and he promoted Su to the post of minister of agriculture in order to do so. Su refused and rebelled, in alliance with Zu. Yu, initially believing that he could defeat Su easily, declined assistance from provincial officials, including Wen's Jiang Province (江州, modern Jiangxi) forces, but instead Su quickly descended on the capital Jiankang (name changed from Jianye due to naming taboo of Emperor Min's name) and captured it in early 328, taking Emperor Cheng and Empress Dowager Yu and forcing Yu Liang to flee to Wen.