The Legacy of King An Duong

Shannon
5 days ago
5 min read

The Making of a Warrior King

In the 3rd century BC, Thuc Phan rose from the turbulent political world of ancient northern Vietnam to become An Duong Vuong, the ruler who defeated the last Hung king and founded the kingdom of Au Lac nearly 2300 years ago. He had taken the throne through conquest and his new kingdom immediately faced the threat of Trieu Da, the ambitious ruler of neighbouring Nam Viet. An Duong Vuong responded by moving his capital to Co Loa, where he raised a fortress of extraordinary scale, its enormous earthen ramparts twisting through the countryside in successive rings. Moats filled the spaces between them, while gates and fortified approaches turned the road to the royal centre into a maze designed to exhaust, confuse and trap an invading army. Co Loa was a capital but it was also a warning written into the earth. Whoever wanted An Duong Vuong's throne would have to fight their way through the kingdom he had built around himself.

Stone statue of a figure playing a flute stands on a pedestal in a green pond, surrounded by lush trees and foliage in the background.

The Claw of the Golden Turtle

The legends of Co Loa give its foundations a far stranger history. The walls repeatedly collapsed during construction, destroyed each night by hostile supernatural forces that resisted the king's attempts to complete his stronghold. An Duong Vuong eventually sought the aid of Kim Quy, the Golden Turtle, an ancient supernatural being who appeared at the site and drove away the force responsible. Before leaving, Kim Quy gave the king one of its claws, which was fashioned into the trigger of a miraculous crossbow. In legend, this was no ordinary bow. Its power was so vast that a single discharge could unleash a devastating volley upon an enemy army, making the walls of Co Loa even more formidable. The image is wonderfully strange. An enormous fortress rising from the soil, guarded by deep water and towering ramparts, with a raw turtle claw hidden inside the mechanism of the weapon that supposedly made the kingdom untouchable.

Traditional gate with ornate roof tiles and foliage, featuring trimmed bonsai trees in pots. Blue sky and lush greenery surround the scene.

An Army Buried in Bronze

Beneath that legend lies an extraordinary archaeological reality. Co Loa has yielded vast quantities of bronze arrowheads, including distinctive three pronged examples that were manufactured in huge numbers, together with evidence of bronze casting and metalworking. The ancient settlement was therefore capable of producing enormous quantities of military equipment, transforming molten bronze into sharp little instruments of death. Thousands of these arrowheads have survived long after the hands that cast them and the soldiers who carried them disappeared. They were made for the walls, the gates and the armies gathering beyond them and their sheer abundance gives Co Loa a grim physical presence. The miraculous crossbow belongs to legend but the bronze barrage that surrounded it has left its mark in the ground.

Weathered stone relief of warriors with spears and shields on a carved wall, in faded gray and pink tones.

The Enemy Inside the Palace

Trieu Da eventually found a way to approach the fortress without first having to conquer it. His son, Trong Thuy, was sent into the royal household and married My Chau, the daughter of An Duong Vuong. The marriage placed the enemy prince beside the king's own family, giving him access to the secrets hidden behind the walls. In a quieter form of warfare, Trong Thuy learned about the sacred claw that gave the crossbow its power and discovered the weakness on which the entire defence of Au Lac depended. The fortress was surrounded by ramparts and moats but none of them could stop a man who had already been welcomed through the gates. Co Loa had been designed to keep an army out. It had never been designed to keep a trusted son in law from reaching the king's most closely guarded secret.

Stone guardian dog statue on a temple altar, framed by red lanterns and a green flower offering, glowing warm and ornate.

Secrets That Broke the Empire

Trong Thuy stole the sacred claw and took it back to his father, Nam Viet, leaving An Duong Vuong with a weapon that could no longer perform the miracle upon which his confidence rested. When the invasion came, the king reached for the crossbow that had once made his enemies powerless and found that its supernatural strength was gone. The enormous walls of Co Loa could still hold but the defence behind them could no longer deliver the destruction the king expected. An Duong Vuong fled Co Loa with My Chau as the forces of Nam Viet pursued them, leaving behind the capital whose immense walls had been built to withstand precisely such an attack. The enemy had already crossed the ramparts in the guise of a husband.

Historic temple gate with Chinese characters, stone steps, and colorful flags, framed by trimmed shrubs under a blue sky

The Princess, the Feathers and the Sea

My Chau did not know that the man she loved had betrayed her family. As she fled with her father, she scattered feathers from her clothing along the road, leaving a trail for Trong Thuy to follow. The white down marked their escape until the pursuing forces closed in at the coast, where the Golden Turtle appeared again and revealed the betrayal. Faced with the ruin of his kingdom, the king turned upon his daughter and killed her, spilling her blood onto the earth before following Kim Quy into the sea. According to the legend, her blood was carried into the water and became pearls within oysters, while Trong Thuy later returned to a well associated with her memory and took his own life. The lovers who had helped destroy the kingdom were separated in death, yet their story remained bound to the places where the betrayal had unfolded.

Five ornate swords with gold accents are displayed on a carved wooden stand against a textured beige wall, creating a historic and elegant mood.

Relics of a Fallen Kingdom

Co Loa did not remain the centre of power for long. After the fall of Au Lac, the fortress passed into the history of successive kingdoms, its immense earthworks gradually fading as villages, temples and shrines claimed the ancient lines of defence. Yet time failed to erase the geometry of the stronghold. Today, those monumental spiral ramparts still ripple through the earth, visible from above like shockwaves frozen in the dirt. A capital built for war became an ancient ghost city, quietly swallowed by the modern life that inherited its ruins, while its silent loops continued to hold down the mud where Vietnam’s oldest royal tragedy took root. This is the legacy of King An Duong, preserved in the physical outline of a kingdom that could manufacture its own protection, yet could not protect itself from betrayal.

Ancient pagoda pavilion with curved roof and dragon statues, framed by lush trees and stone steps in bright sunlight.

🗺️ Location

Co Loa Archaeological Site, Thon Chùa, Co Loa Commune, Đong Anh District, Hanoi, Vietnam

🚆 How to get there

The citadel is located in Đong Anh District, around 20 km's northeast of the city centre and takes about 45 minutes to reach, depending on traffic. You can take a taxi for about 200000-300000 VND each way. Make sure you negotiate a fair price with the driver and make sure they wait for you and return you to Hanoi. If you prefer a more local experience, you can rent a motorbike and follow Highway AH14 or Vo Chi Cong Road across the Nhat Tan Bridge, then continue along Quoc Lo 3 until you see signs for Co Loa. Public buses also run from Long Bien or My Đinh Bus Stations, with Bus 17 being the most common route - though slower, it’s cheap and reliable. Once you arrive, the entrance is easy to spot and the main path leads straight to the ancient spiral ramparts and temple complex.

⭐ Attraction Info

Co Loa Citadel welcomes visitors daily between 8am - 5pm, with tickets priced at 30,000 VND. Despite its historical importance and proximity to Hanoi, the site remains remarkably quiet, offering a peaceful escape from the bustling city. Visitors can wander through the ancient grounds, explore the spiral ramparts and visit the temples and shrines that dot the complex, all while taking in the quiet northern plains. The calm, open spaces make it easy to imagine the kingdom at its height and to reflect on the legends and history embedded in every wall and pathway.