At the end of the Hung Kings period, at the beginning of the third century BC, a large and powerful empire was unified in the North: the Qin Dynasty, waged a war of aggression with a large scale, the number of troops reaching 50,000, led by Do Thu, went to the South to "pacify Bach Viet". In the first 3 years, the Qin army captured the state of Chu, establishing 3 districts of Guilin, Nam Hai and Tuong. But when proceeded down the South, which is the land of Tay Au (Au Viet), they faced many difficulties because they were not familiar with the land, lack of food, and were resisted by the Vietnamese people in the " sometimes to conceal, sometimes to reveal" style, so they did not can win and fall into the "dilemma".

Thuc Phan was a leader of Tay Au in the northern area of Van Lang at that time, and together with many chieftain of Tay Au and Lac Viet organized the resistance war against the Qin army. In 208 BC, the Qin dynasty had to withdraw from the army and retreat to keep the land of the 3 districts captured in the North.

During the resistance war against the Qin army, Thuc Phan stood out as a talented leader who had great prestige for the whole of Tay Au and Lac Viet. In fact, the communities of Lac Viet and Tay Au residents have formed and become more solid through joining hands to fight the invaders. That created the basis for the birth of a new alliance - a new State, in which the leader with full talent and prestige is Thuc Phan.

In 208 BC, Thuc Phan proclaimed himself King, founded Au Lac, followed the career of King Hung - an event of special significance in the development process of the nation's history. Au Lac country is the merger of two tribes Lac Viet and Au Viet, not the result of a war of annexation. It represents a new development step of the ancient nation of the Vietnamese ethnic groups, a continuation at a higher level than Van Lang and also an indispensable requirement of history.

In this historical context, An Duong Vuong with a strategic vision and strong determination to build and defend the country, decided to move the central position of the country from the old land of Hung Vuong to the the plains, larger and more favorable, established the capital, built a citadel to fight the enemy. That is the land of Co Loa today.

With an extraordinary effort, An Duong Vuong and Au Lac army and people built a massive and unique citadel in a short time. With an extraordinary effort, An Duong Vuong and Au Lac army and people in a short time built a massive and unique citadel. An Duong Vuong - the commander and the designers knew how to make full use of the natural elements of the topography to create a deep moat citadel with enough favorable factors for defense and attack: the connection between waterway and road, inside and outside combined, we can advance and retreat quickly, the enemy is difficult to invade. That is the citadel that used to be called Oc citadel, Tu long citadel, Loa citadel or Co Loa citadel today.

Co Loa citadel, as the capital of Au Lac, also meant the political, economic and social center of the country at that time. Thanks to the unity of the army and people, the "God of the Cross" and that unique citadel, An Duong Vuong defeated the invading Trieu Da army many times. 

According to the ancient custom of the locality recorded in the book "Ngoc Pha Co Luc", the 7th day of the 3rd lunar month is the day of "the death of the king", also known as the anniversary of the death of King An Duong Vuong - the king who built the country in in the 3rd century BC, the feudal dynasties had ordained gods and was worshiped at Thuong temple, Co Loa relic site, Co Loa commune, Dong Anh district, Hanoi city. In order to pay tribute to ancestors, to educate the traditional morality of when drinking water, think of its source, on the anniversary of the death of King An Duong Vuong on the 7th day of the 3rd lunar month every year, Thang Long - Hanoi Heritage Conservation Center, Management Department of Cổ Loa Vestige Site, together with the Party, government and people of Co Loa commune and Dong Anh district, respectfully offer incense to commemorate King An Duong Vuong at Thuong temple, Co Loa relic site.

Statue of King An Dương Vương

MANAGEMENT DEPARTMENT OF COLOA VESTIGE SITE