During the fall of the Song Dynasty and the formation of the Sino-Mongolian “Yuan” Empire，Vietnam experienced what they called “barbarian invasion from the north”.The Mongolians achieved much military success during their Asian campaigns，but Vietnam forces managed to break the Mongolian offensive forces.This victory not only ensured Vietnamese autonomy during the height of Mongolian domination in Asia，but also deeply affected how history developed in Vietnam and the greater south-western region of China.How did Vietnam ward off the powerful Mongols？This paper focuses on Vietnamese epigraphic data，and provides an analysis of the political situation in southeastern Asia during the Mongolian offensive.

Funerary Stele of Princess Feng Yang provides ample genealogical information that could be systematized into a detailed imperial genealogy for the Tran Dynasty.The genealogy reveals a political structure that is a feudalistic aristocracy based on consanguinity；Hu’ng Vu’o’ng was the central figure who organized the upper class aristocracy into a fighting force that has the military means and cohesiveness to fend off Mongolian forces.

“ Thông Thánh quán chung ky” is a inscription that relates historical accounts of the Tran Dynasty.A section dealt with the Mongol invasion and how remnant expatriates of the Song Dynasty forged an alliance with imperial forces of the Tran Dynasty to fight the Mongols.These remnant expatriates are by no means equal in respect to their devotion to the resistance，however；members of different social status were clearly varied in terms of their willingness to continue another war against the Mongols.Contrast such reluctance among the Song Dynasty expatriates，inscription from the Xing Fu Si Stele show glimpses of willing groups of Vietnamese local strongmen being the primary benefactors to Vietnam’s successful defense.

Military success achieved by the Tran Dynasty was groundbreaking，because Vietnam was able to maintain de facto autonomy，and was able to extend its power to other parts of Southeastern China，and carve out a sub-suzerainty for itself.