Pei Ju
Emperor Wen died in 604 and was succeeded by his son Yang Guang (as Emperor Yang), and initially, the relationship between Tuyuhun and Sui remained peaceful, with Murong Fuyun sending emissaries to submit tributes to Emperor Yang in 607, along with emissaries from Gaochang and the khan of Eastern Tujue himself, the Qimin Khan Ashina Ran'gan. However, later that year, the Sui official Pei Ju returned from a tour of the Xiyu states, and knowing that Emperor Yang was looking for targets to conquer, suggested to him that Xiyu states had a lot of treasures and that Tuyuhun was easy to conquer. Emperor Yang started considering attacking Tuyuhun, as a result. At one point, when Murong Fuyun sent Murong Shun as an emissary to Sui, Emperor Yang detained him.