《新唐书·列传·卷二十六》
炀帝巡视雁门关，被突厥围困，萧瑀献计说 ：突厥的习俗，可汗的妻子可贺敦参与军事活动，何况义成公主是以大隋皇帝女儿的身份当了可贺敦。
帝至雁门，为突厥所围，瑀谋曰： 夷俗，可贺敦与兵马事，况义成公主以帝女为之。
Emperor Yang patrolled the Yanmen Pass, was besieged by the Turks, and Xiao Yu suggested: "According to the customs of the Turks, the Khan's wife, Kehe Dun, can participate in military activities, not to mention that Princess Yicheng became Kehe Dun as the daughter of the Emperor of the Great Sui Dynasty.