Meanwhile, another Sui general named Li—Li Yuan the Duke of Tang, who had been in charge of Taiyuan (太原, roughly modern Taiyuan, Shanxi) to guard against Eastern Tujue's attacks—rebelled at Taiyuan, claiming that he wished to support Emperor Yang's grandson Yang You the Prince of Dai, then nominally in charge at Chang'an, emperor. Li Yuan initially wrote Li Mi, trying to see if Li Mi would be willing to follow him, but Li Mi, believing in his own strength, had his secretary Zu Junyan (祖君彥, the son of the Northern Qi prime minister Zu Ting, whom both Emperor Yang and his father Emperor Wen had rejected as an official because Zu's false accusations against Hulü Guang had led to Northern Qi's downfall) write Li Yuan for him in this way: