 In 533, Yuwen volunteered to serve as messenger to Gao in order to observe Gao's abilities, and Heba agreed.When Gao met Yuwen, Gao was impressed by the answers Yuwen had to his questions and wanted to detain Yuwen, but Yuwen left Gao's domain before Gao could seize him.Subsequently, Heba sent Yuwen to confer with Emperor Xiaowu, who was not happy about Gao's hold on power, and Emperor Xiaowu and Heba were able to enter into a secret alliance against Gao.