In ancient times, the land of Lạc Việt was plagued by many monsters that disturbed the peace and prevented the people from living in harmony. Lạc Long Quân, a god of dragon descent who lived in the underwater realm, possessed extraordinary strength. From time to time, he would come ashore to help the people by destroying the monsters and teaching them how to farm, raise livestock, and live properly.
Not long after, Âu Cơ became pregnant and gave birth to a sac containing one hundred eggs, which later hatched into one hundred sons. The children grew rapidly, all of them handsome and strong. However, being accustomed to life underwater, Lạc Long Quân found it difficult to remain on land for too long. Saddened, he had to part ways with Âu Cơ, but not without promising her, "Whenever you need me, we will meet again.
Lạc Long Quân took 50 of their children to the sea, while Âu Cơ led the other 50 to the mountains. The children divided the land and ruled over different regions. The eldest son became king, taking the title Hùng Vương, establishing his capital in Phong Châu, and naming the country Văn Lang, thus marking the beginning of the era of the Hùng kings.
From this legend, the Vietnamese people proudly trace their ancestry back to the Dragon and the Fairy whenever they speak of their origins.