Trang An Festival dates back to the Dinh Dynasty (10th century), associated with King Dinh Tien Hoang choosing Hoa Lu as the capital and constructing the Vu Lam Royal Step-over Palace (now in Truong Yen Commune, Hoa Lu District).
- According to legend, after ascending the throne, King Dinh organized a procession to honor the Water Dragon deity to pray for favorable weather, national peace, and prosperity.
- Local people believe that the Water Dragon brings irrigation water to the Truong Yen rice fields and protects the ancient capital land from natural disasters.
- Since then, every year in the third lunar month—at the end of the spring crop—locals host the festival to express gratitude to the gods and pray for a bountiful harvest.
Today, the festival also signifies gratitude to forefathers who contributed to building and defending the nation, while promoting the beauty of Trang An to the world. A unique feature of the festival is the “Phat Lac” ritual (forest opening)—an ancient convention reflecting respect for nature, where locals harvest forest products only within limited boundaries on a single day of the year. This is considered an early cultural tradition of environmental protection by the indigenous community.


