Yelü Bei
Emperor Taizong, however, would never reach Liao proper, as he fell ill on the journey and died near Heng Prefecture (恆州, in modern Shijiazhuang, Hebei). His nephew Yelü Ruan the Prince of Yongkang then claimed imperial title (as Emperor Shizong) (after preemptively arresting Zhao, who had planned to declare himself emperor of China). As Emperor Shizong saw the likelihood that his grandmother (the mother of both Emperor Taizong and his own father Yelü Bei) would oppose his succession, he took the main Liao army and continued back toward Liao proper, leaving an army at Heng (which Emperor Taizong had designated as the middle capital) as its garrison, along with many Han officials, including Zhang. When Xiao and Emperor Taizong's cousin Yelü Mada () subsequently withdrew from the Central Plains to Heng as well, they, still bearing grudges over Zhang's suggestion of commissioning only the Han Chinese to rule the Han Chinese, had their soldiers surround Zhang's mansion. At that time, Zhang was already ill, but he came out to meet Xiao and Yelü Mada. Xiao rebuked him, stating: