Dai Tu Communal House (Tam Giao Temple)

1. Location
Dai Tu Communal House is located in Dai Tu village, Hoai Duc commune, Hanoi city, and is one of the typical historical-cultural relics associated with the worship of Ly Nam De (Ly Bi) in the Hoai Duc area. According to historical documents, Dai Tu village was formerly known by its vernacular name Thia village, in Dan Phuong district, Quoc Oai prefecture, Son Tay garrison, and later transferred to Hoai Duc district, Ha Dong province.

2. 2. Architecture and landscape
Dai Tu Communal House has a Dinh-character (丁) architectural layout, consisting of two main components: the Dai Bai (main hall) and the Hau Cung (rear shrine). This is a common layout in traditional Vietnamese village communal house architecture, in which the Dai Bai is the space for ceremonies and community activities, while the Hau Cung is the place of worship for the village tutelary god.
The communal house still preserves many valuable artifacts such as the ceremonial gate, eight precious weapons, incense table, altar couch, palanquin, incense bowl, along with a system of royal edicts. Published documents state that the communal house once kept many royal edicts from the Le dynasty to the Nguyen dynasty, which are important materials contributing to affirming the historical and religious value of the relic.
The architectural space of the communal house blends with the landscape of green trees, ponds, and the old village space, creating the characteristic architectural – landscape – religious ensemble of a Northern Delta village communal house.

3. Historical figure
Dai Tu Communal House worships Ly Bi, also known as Ly Bon, with the title Ly Nam De, as the village tutelary god.
According to the spirit genealogy passed down by the community and recorded in the festival inventory form, Ly Bi was born on the 12th day of the 9th month of the Quy Mui year (503). He was a man of both literary and martial talent and led the people to rise up against Northern domination. After victory, in 544, he ascended the throne as Emperor, proclaimed himself Nam De, established the country name Van Xuan, and opened an independent state in the nation's history.
Dai Tu is an area associated with Ly Bi's activities in the early years of preparing forces. According to materials in the inventory form, around 540–541, Ly Bi chose the area that is now Dai Tu to recruit troops, organize talent contests, train soldiers, and prepare food. On the 7th day of the 3rd month of the Tan Dau year, he held a troop feast and raised the army against the Liang. After victory, he ascended the throne as Nam Viet De and named the country Van Xuan. Those historical traces and legends became the basis for the people of Dai Tu to build a communal house for worship and to commemorate the king's merits in building and defending the country.
Besides Ly Nam De, the communal house also jointly worships Trinh Do Ho Quoc and Tam Do Ho Quoc, generals traditionally credited with assisting Ly Nam De. Materials about the relic state that Trinh Do and Tam Do were associated with this land and sacrificed their lives in the war against the Liang army.

4. Festival
The traditional festival of Dai Tu village is a long-standing folk cultural activity closely tied to the worship of the tutelary god Ly Nam De. According to the inventory form, the festival dates from the 6th century; due to the effects of war, there were periods when it was not held. In 1990, the festival was restored and has since been maintained annually.
The main festival is held from the 7th to the end of the 9th day of the 3rd lunar month, with the 7th day of the 3rd month being the main day. Every five years, the festival is held on a large scale with all traditional rituals such as offerings and palanquin processions; in other years, a communal festival is held, mainly performing offering rituals at the communal house.

5. Ranking
With outstanding historical, cultural, architectural, and artistic values, Dai Tu Communal House was ranked by the Ministry of Culture and Information as a National Architectural and Artistic Relic in 1990.