Thanh Dong through ancient books

Hai Duong provincial citadel (also known as Dong citadel) is an ancient citadel built under the Nguyen dynasty. This was both an administrative center of the region and a large-scale and solid military project. After more than 200 years of construction, the old Dong citadel no longer exists, but through the woodblock heritage information pages, we can understand more about the establishment and planning methods of the Nguyen dynasty in the process of building, developing and protecting the territory.

The reason why Hai Duong province is called Thanh Dong is because Hai Duong province also has another name, Dong province. Therefore, the name of the city is also called the town of Dong region (abbreviated as Thanh Dong) to distinguish it from Doai region. Regarding Hai Duong province, the book Dai Nam Nhat Thong Chi, volume 17, section on Hai Duong province citadel, recorded that: “Hai Duong province citadel: ... Located in the communes of Ham Giang, Ham Thuong and Binh Lao, Cam Giang district. During the reign of Le Quang Thuan, the town's headquarters was in Mac Dong commune (commonly called Dinh Le), Chi Linh district, later moved to Mao Dien commune (commonly called Dinh Dau), Cam Giang district...”.

However, in February of the year Giap Ty (1804), King Gia Long moved to Ham Giang commune.

During the reign of King Gia Long, the citadel of Hai Duong province was built with earth. Over time, when he saw that the citadel of Hai Duong was badly damaged, the Governor of Bac Thanh, Le Chat, reported to the king: "The citadels of the two provinces of Bac Ninh and Hai Duong have mostly collapsed. Please take advantage of the time when rice is scarce and hire people to rebuild them." With the consent of King Minh Mang, in the fall of the year Giap Than (1824), the citadel of Hai Duong was rebuilt with laterite.

The location and scale of Hai Duong citadel are recorded in the history and geography books of the Nguyen Dynasty. All of them record the consistent location of the citadel in Ham town. However, there are different records regarding the scale. The wooden block of the book "Kham dinh Dai Nam hoi dien su le", volume 209, engraved on page 38, states: "Hai Duong citadel is located in Cam Giang district, Binh Giang prefecture, with a perimeter of 582 truong 5 thuoc 4 tac, a height of 1 truong 1 thuoc 4 tac, built of laterite, with four gates, a flagpole, and a moat 7 truong 2 thuoc 5 tac wide". Meanwhile, in the book "Dai Nam nhat thong chi" it is written: "Hai Duong citadel: perimeter of 551 truong 6 thuoc, a height of 1 truong 1 thuoc 2 tac. The citadel body has 6 corners, opens with 4 gates, a moat 11 truong wide, and a depth of 6 thuoc".

Although there are different records, with this structure, it can be seen that Hai Duong citadel was built in the Vietnamese citadel architecture style, built in Vauban architecture, including the inner and outer citadel.

In the year of Dinh Mao 1867, King Tu Duc also built Duong Ma citadel at the gates.

Although Hai Duong citadel is considered one of the most solidly built citadels with high walls and deep moats, over time, the citadel was severely damaged. In the year of Nham Ngo 1882, after Hanoi citadel fell, the French army gradually invaded the North. By February of the year At Dau (1885), the French army had attacked a southern corner of the Eastern citadel.

In the year of Ky Suu 1889, many sections of the Hai Duong province citadel wall were demolished by the French colonialists to make way for the construction of a winery and several French mansions. During the period of 1946-1954, due to fierce fighting, most of the remaining relics of the citadel were also severely damaged.

Through ancient documents, Hai Duong provincial citadel is not only known as a specifically planned and unique architectural work. Under the Nguyen Dynasty, Hai Duong provincial citadel also played a very important role in military and politics, not only for Hai Duong province but also in the defense line of the northern provinces, especially for Thang Long citadel.