Four Great Treasures of Annam

State historical documents record construction of a 12 or 13 level tower[2] in 1057 with 12,000kg of bronze being used to create a bell mounted at the top of tower where doors were also made from bronze. The tower was 80 meters high, considerably higher than other structures, but inherently weak: in 1225 the peak of the tower fell during a storm, and the top partly collapsed again in 1322.

Finally, the tower was destroyed by the Ming in 1414 during the Fourth Era of Northern Domination of Vietnam.[3] The Bao Thien Temple was repaired in 1434 but was abandoned later during the Revival Lê dynasty. The site became a place of market, and the ground of the tower itself was covered to become hills and a place of execution.[4]

In 1880s, part of the site of the abandoned temple was used to build the Great Church or St. Joseph's Cathedral.[5]

Around 1049, the One Pillar Pagoda was built in the centre of a pond and during renovations to the building in 1105, a huge bell, named Giac The Chung - the bell that awakens people in the world - was constructed from 12,000kg of bronze. However, the bell was too heavy to be hung and since it could not be rung on the ground, it was dropped into a deep rice field nearby. The bell was later found to be surround by tortoises and hence it was renamed Quy Dien Chung - tortoise-field bell.

During the Ming invasion, in 1426, the bell was also requisitioned by Ming General Wong Tong to be used to make weapons.

The one-pillar pagoda was renovated several times between 1840 & 1850 and also 1922.[6]

The Quynh Lam Pagoda was original constructed at the start of the 6th century and restored & improved on numerous occasions. During the 11th century Quynh was an important centre for Buddhism becoming the primary centre for the entire country in the 17th & 18th centuries.

In the early 14th century, 1328, a statue of Maitreya was cast standing almost 5m tall and visible from miles around. It is recorded that 900kg of gold was contributed to the statue. The statue was the largest at the site but it is recorded that the monk Pháp Loa had more than 1,300 big and small bronze statues cast plus another 100 earth statues.[7]

During the Ming invasion of the early 15th century the pagoda was reduced to ruins and the statues destroyed.

The Phổ Minh Pagaoda was built during the Lý Dynasty and expanded in 1262. The entrance was guarded by a 7 tonne bronze cauldron which was big enough to contain two adults.

While the pagoda survives, the cauldron suffered the same fate as other bronzes during the early 15th century Ming invasion.[8]