Mount Tản Viên is considered by many today to have been a sacred site for Vietnamese since antiquity. Stories about the spirit of Mount Tản Viên can be found in early Vietnamese texts, and they contain information about this mountain alongside reference to the Hùng kings, who supposedly ruled during the BC period. The connection between the Vietnamese and this mountain therefore would seem to have ancient origins.
However, there are problems with this picture of the supposed antiquity of the relationship between the Vietnamese and Mount Tản Viên. The first is that linguists believe that the Vietnamese (by which I mean people who spoke early versions of the language we today refer to as Vietnamese) originated somewhere in what is today central Vietnam and eastern parts of Laos. In the BC period, much of the Red River delta was inhabited by non-Vietnamese peoples, such as speakers of Tai and Kadai languages.
So before the Vietnamese came in contact with Mount Tản Viên, it should have been familiar to other people already. How long did it take for Vietnamese to appropriate this mountain into their beliefs and to displace these earlier inhabitants?
If you disregard the stories about Mount Tản Viên and the Hùng kings at the beginning of the Đại Việt sử ký toàn thư and look for actual historical references to this mountain in that text, you find the following information:
1) In 1073 there were constant rains, so emperor Lý Nhân Tông had a Buddha image from Pháp Vân pagoda brought to the capital so that he could seek its power in praying for clear skies. He also had offerings made on Mount Tản Viên.
2) In 1129 Emperor Lý Thần Tông heard a report that there was a white deer on Mount Tản Viên and sent someone to catch it. Like the importance of white elephants in the Burmese-Tai world, it is likely that this white deer was seen as a sign of power. Nonetheless, it (or its presence on Mount Tản Viên) may have also been seen as related to rain because right before this entry in the Đại Việt sử ký toàn thư it states that the emperor fasted and prayed for rain, as apparently there was a lack of rain at that time.
3) In 1145 a spirit shrine was constructed on Mount Tản Viên.
So in the late-11th century we find a Vietnamese ruler ordering that an offering be made on Mount Tản Viên in connection with rain. Over 70 years later another ruler ordered a shrine built on the mountain.
Perhaps there was a shrine on the mountain prior to this point. If there was one, the text probably would have said that the emperor ordered the shrine renovated, as it was a common practice to renovate shrines. However, we can’t be sure here one way or the other. Nonetheless, what is significant is that these entries demonstrate that Vietnamese were venerating the spirit of Mount Tản Viên at this time.
Another point which is significant is that after these entries about Mount Tản Viên in the Đại Việt sử ký toàn thư we find other references to Mount Tản Viên which refer to the “savages” which live around it. In 1207 Mount Tản Viên “mountain savages” (山蠻) plundered, and in 1226 they fought with neighboring savages.
This information from the Đại Việt sử ký toàn thư sure doesn’t make it look like the Vietnamese have venerated Mount Tản Viên since antiquity. To the contrary, these entries make it look like this was a practice which was just beginning around the 10th and 11th centuries.
Could it be that the stories about Mount Tản Viên and the Hùng kings are merely that – stories?