The Four Great Treasures of Annam were four bronzes typical of the culture of Lý and Trần dynasties of Vietnam. They were: Bao Thien Tower, Quy Dien Bell, Buddha Statues of Quynh Lam Temple and Pho Minh Caldron. None of these survive.
State historical documents record construction of a 13 level tower in 1057 with 12,000kg of bronze being used to create a bell mounted at the top of tower where doors were also made from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, and inherently weak: in 1225 the peak of the tower fell during a storm, and the top partly collapsed again in 1322.
In 1426 during an invasion by Ming troops, Ming General Wong Tong ordered the bronze to be taken to make weapons but is unlikely that he ordered the tower itself to be destroyed.
The tower apparently still exist in 1490 and is depicted on a contemporary map.
The tower collapsed again in 1542 and was never repaired or replaced.
In 1791 some of the few remaining structure of the tower was recycled to repair the nearby citadel.
Finally, the tower was declared unsafe and torn down to be replaced in 1864 by a Christian church - now known as the Great Church or Hanoi Cathedral.
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 tower was too heavy to be hung. Since it could not 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.
The Quynh Lam Pagoda was original constructed at the start of the 6th century and restored & improved on numerous occasions. Since the 11th century Quynh was an important centre for Buddhism to become 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 Phap Loa had more than 1,300 big and small bronze statues cast plus another 100 earth statues.
During the Ming invasion of the early 15th century the pagoda was reduced to ruins and the statue destroyed.