Son Tay ancient citadel is known to many people for its precious cultural and historical values associated with its role as the center of a region of Doai, once located west of Thang Long citadel. It has affirmed the role and position in terms of economic, military, cultural, and trade factors of a diverse and large geographical area. Doai region culture is an important pole in the existence and common development of the culture of ancient Thang Long and today's capital Hanoi.

Son Tay ancient citadel is 200 years old (1822 - 2022), established during the 3rd year of King Minh Mang (1822). The Nguyen Dynasty had to send mandarins from the region to search and select for the third time to find a location and land favorable to heaven - earth - people to build the citadel.

The laterite citadel was built in the architectural style of Vauban (an engineer who later became a marshal of France), converging the elements and properties of a solid military citadel with military and defense works. Footprint Vietnam Travel. The palace, the office, the flag tower, the city wall, the four gates, the governor's house, the armory, the residences of mandarins and soldiers and their families, and even prisons...

Son Tay ancient citadel has existed and is also known as the town of Son Tay province since 1831. The citadel existed for 61 years under the reigns of the Nguyen Dynasty (1822 - 1883) before being attacked by the French expeditionary force. After three attacks from Hanoi by waterway and road to the citadel, the French army was able to defeat the citadel with the strength of their weapons, combat experience, and superior plotting tactics. In addition to the great value of its military defense position, the center of economic, cultural and social development of the whole region (today, near the Bac Thanh gate, there is also the Hung Hoa Bishop's Palace, which is also the headquarters for the province). Catholic activities of the Western and Northeast provinces). Son Tay ancient citadel with its large and majestic old buildings has proven the hard work and creativity of the people, scholars, and soldiers inside and outside this Doai region. Therefore, in 1924, the governor-general of Indochina issued a decree classifying items in the ancient citadel, including the Vong Cung palace, as cultural heritage of An Nam and assigned it to the School of the Far East to manage.

With a total area of 20 hectares, including 16 hectares of ground, 4 hectares of water surface (the moat has a length of 1,795m, running around the citadel, the drain into the moat is taken from the Red River, the drain out is opened and pushed into the Tich river). Son Tay ancient citadel has a quadrilateral shape, with a circumference of 1,394m. Although before being classified as a cultural and historical relic by the state in 1994, the construction items in the citadel relic were almost gone and looking at them were only vestiges of old foundations. What remains over the years are two ancient gates, West and South, two water wells and a system of trees and grass. Until now there have been a number of items inside and outside the monument that the state has invested in restoring according to the old model such as: Vong Cung, Ky Dai, campus, Doan Mon, laterite wall around the three dimensions of the gate. West - South - North and a system of walls and sidewalks made of blue stone. Historical sources about the ancient citadel are also provided to the locality by many scholars and people inside and outside the town to serve the work of managing, preserving and embellishing the monument, including documents left by the French during their military march to the Son Tay region at that time.

It can be affirmed that: Son Tay ancient citadel still exists spatially intact to this day, from the surrounding bustling neighborhoods, passing through the moat (2 gates) is a relic area dating back 2 centuries, a quiet, airy forest in the heart of the town, surrounded by heritage, covered with green leaves in all four seasons, which is a huge contribution of the community.

Coming to the citadel, everybody feels like they can reminisce and admire a unique citadel with outstanding values ??in terms of architecture, age, fine arts, location, and citadel construction techniques. Laterite was the main building material, unlike other citadels in the Tonkin at that time that were built with terracotta bricks or green stone. Through the stages, the works in the citadel continued to be consolidated. It is worth noting that a whole road was also designed in the citadel, which people call "Tuong Dao" (the path of the elephant). There is an elephant belonging to the Governor of Son Tay that has been passed down with very emotional stories between it and the owner in the battle to protect the citadel.

In addition, the Son Tay ancient citadel also contains valuable resources such as the well water drilled from the southern laterite seam was explored and discovered by the French in 1932, after which a water pumping station was built to serve the daily needs of the people around the citadel, most especially is tens of thousands of large and small species living and growing, including animals and plants from different levels and species such as above ground, underground, under water. The soil in the citadel must have many nutritional elements to add vitality to the growth of all species of trees.

Son Tay ancient citadel has become a precious cultural tourist destination that attracts a large number of visitors who must visit when on their trip to Son Tay. It is a red address in the Doai region cultural area, the gateway to the west of Hanoi capital city.