Citadel of the Ho Dynasty with total area of 5,234ha was the capital citadel of Viet Nam from 1398 to 1407. The citadel of the Ho Dynasty is also known as names of An Ton, Tay Do, Tay Kinh, Tay Giai, Thach Thanh.

◊ History 

The citadel of the Ho Dynasty was built for 3 months in 1397 by Ho Quy Ly who was the highest-ranking mandarin of Tran Dynasty. According to the feng shui principles, it was sited in a landscape of great scenic beauty on an axis joining the Tuong Son and Don Son mountains in a plain between the Ma and Buoi rivers. After the citadel was completed, Ho Quy Ly forced King Tran Thuan Tong to move the capital from the citadel of Thang Long (Ha Noi) to Thanh Hoa. In 1400, Ho Quy Ly crowned to replace King Tran and renamed the country as Dai Ngu, the citadel of the Ho Dynasty official became the capital citadel until 1407 with the name of Tay Do.
 

◊ Outstanding Impressive Architecture
 

The citadel of the Ho Dynasty is an architectural masterpiece of the 14th century with impressive architecture of the walls and other parts. Thanks to the unique construction techniques, all the major stone sections are intact and have not been affected by time and weather or by recent urban encroachment. The citadel buildings represent an outstanding example of a new style of Southeast Asian imperial city with a combination between the Vietnamese architecture and the unique building techniques of Viet Nam, Southeast Asia and Eastern Asia.

The complex of the citadel of the Ho Dynasty includes Thanh Noi (Inner Citadel), Hao Thanh, La Thanh and Nam Giao Altar (for worshipping the Heaven). 

Thanh Noi is the main architectural work of the citadel, also known as Imperial Citadel with the remains of the royal palaces and temples inside. It is fairly square with about 870.5m long north and south sides, 883.5m long east and west side.. Thanh Noi has four domed gates called the South, North, West and East (or also known as the Front, Back, Left and Right gates), each located at the centre of each side. The Front Gate in the south is the most important and has three entrances.
 

According to the documents, there were palaces in the Thanh Noi such as Hoang Nguyen, Nhan Tho, Phu Cuc, Dong Cung, Dong Thai Mieu, Tay Thai Mieu, Diem Canh… However, now Thanh Noi remains some relics such as a part of the citadel’s wall and four gates, vestiges of lakes, a couple of stone dragons with sophisticated carving features, foundation of Thanh Noi architecture, Hoa Nhai marble-paved road, stone balls, stone bullets, pottery, the Southern gate precinct and valuable objects with specific characteristics of Tran - Ho dynasties culture.
 

Hao Thanh is the system of water trench surrounded the Thanh Noi and connected with Buoi River through a canal at the southeast corner of the citadel.
 

La Thanh, the outer wall of the citadel built to protect the Thanh Noi was home to residents in the citadel. It was approximately 10km in perimeter and its construction based on the natural terrain.
 

Nam Giao Altar is located in the southwest of Don Son Mountain, on the spiritual pathway directly connected with the South gate of Thanh Noi, about 2.5km away from the citadel of the Ho Dynasty to the southeast. This is the place to sacrifice to the heaven; pray for harmonious rain and wind, peaceful country and happy people, prosperous and everlasting dynasty.
 

Surrounding the Citadel of the Ho Dynasty exists relics, such as: exhibition house; Nang Cave and An Ton Mountain; Dong Mon Communal House; temples of Binh Khuong, Tran Khat Chan; Giang Pagoda, Du Anh Pagoda and Ho Cong Cave, etc.
 

Citadel of the Ho Dynasty was recognized as a World Cultural Heritage by UNESCO in 2011 and a special national relic site in 2012.