During the rainy monsoon seasons, Dong – the Thunder God – liked to visit the Dong village in Van Lang. He returned one rainy day and left a foot mark in the eggplant garden. After the rain, a pretty village girl stepped into his foot print and later gave birth to a baby named Dong.

Baby Dong neither laughed nor talked. Though 3 years of age, he stayed in bed without any movement. One day, a nomadic tribe from the North attacked the country. They burned houses, and robbed and killed many innocent people. Wherever they went, they brought destruction and crime. There was great suffering. The governor Lac Vuong sent messengers throughout the land to find those who could save the land and its people. One day, a messenger came to the Dong village and read out loud the governor’s summon. Hearing the messenger, baby Dong spoke: "Go ask the king to make me an iron horse, iron armor, and an iron whip. With those items, I will defeat the attackers." Surprised, the messenger obeyed and immediately returned to the capital.

Following the messenger’s report, the governor ordered use of all of the iron in storage. He asked the good blacksmiths everywhere to come to work at the capital. People took turns working day and night. Soon they had made enough weapons to fight the attackers. Meanwhile, in Phu Dong village, baby Dong started eating more and more. The villagers helped out by sharing their rice and food. Baby Dong continued to eat until he became a tall and robust young man. He put on the iron armor, picked up the iron whip, and jumped up on the iron horse. Many people followed his leadership into battle.

Dong fought vigorously and miraculously. When his iron whip was broken, he used his hand to pull up the bamboo trees to strike the attackers’ heads. After he defeated the attackers, the people asked him to become their general to protect them and to lead them. Declining their offer and great power, Dong rode his iron horse to the crest of mountain Soc Son in the Yen Viet region and disappeared forever.