Trần Thánh Tông
In 1261, the Vietnamese king Trần Thánh Tông (son of Trần Thái Tông – known to the Mongols as Trần Nhật Huyên) agreed to acknowledge the overlordship of Kublai Khan, and sent tributary envoys to Dadu. Kublai enfeoffed Trần Thánh Tông as "King of Annam" ("Annan guowang"). However in 1267, he rejected the "Six-Duties of a vassal state" of the Mongol Emperor gave, included the permit the stationing of a "darughachi" (regional general) with authority over the local administration. Kublai Khan was dissatisfied with the tributary arrangement, which granted the Yuan dynasty the same amount of tribute as the former Song dynasty had received, and requested greater tributary payments. These demands included taxes to the Mongols in both money and labor, "incense, gold, silver, cinnabar, agarwood, sandalwood, ivory, tortoiseshell, pearls, rhinoceros horn, silk floss, and porcelain cups". Later that year, Kublai required that the Đại Việt court send two Muslim merchants he believed to be in Đại Việt to China in order for them to serve on missions on the Western regions and designated heir apparent of the Yuan as "Prince of Yunnan" to take control of Dali, Shanshan (Kunming) and Đại Việt. This would mean that Đại Việt should be incorporated into the Yuan Empire, which was totally unacceptable to the Vietnamese. In 1274, Chinese refugees from Southern Song fled in 30 boats to Dai Viet.