In the edict to move Vietnam’s capital to Hanoi, Emperor Lý Thái Tổ described this land as the middle of heaven and earth, the center of the four directions. Such a place would bring peace and prosperity, he believed, and deserved sacred protection.
Over the course of the Lý Dynasty, the tradition of worshiping Thăng Long Tứ Trấn, or the Four Sentries of Thăng Long, emerged. These are the four temples dedicated to four deities guarding the cardinal directions of the citadel.
The Eastern Sentry: Bạch Mã Temple
Located in the heart of the Old Quarter, Bạch Mã Temple is the sentry of the east. It was built in the 9th century — the oldest temple of Tứ Trấn — to honor the god Long Đỗ, literally the Belly of the Dragon.
Legend has it that when Lý Thái Tổ moved the court to Thăng Long in 1010, he failed to construct a fortress many times. One day, he sent people to pray to the god Long Đỗ, and they saw a white horse walking out from the temple. By tracing the horse’s footsteps and building the fortress accordingly, they finally succeeded. Deeply grateful, the king changed the name of the temple to Bạch Mã, or White Horse, and declared Long Đỗ as the Thành Hoàng, or the One to Bring Abundance, of Thăng Long.
The temple has four main structures. First is a courtyard featuring huge ironwood columns with stunning carvings. The front shrine is dedicated to the White Horse, followed by the mid and back shrine where Long Đỗ himself is honored.
The Southern Sentry: Kim Liên Temple
Kim Liên is the sacred temple defending the south, here, the god Cao Sơn is worshiped. Cao Sơn was one of the 100 children of Lạc Long Quân and Âu Cơ — the founding legend of the Vietnamese people. He was among the 50 who followed mother Âu Cơ up to the highlands, and he helped Sơn Tinh, the God of the Mountains, defeat Thuỷ Tinh, the God of the Water, and brought peace to the people.
The temple was built in the 16–17th century after the capital relocation, making it the youngest of the four. Over time, the people of Kim Liên Village built a cổng tam quan, or a three-entrance gate, right next to the Kim Liên pond. They also added some buildings and turned the temple into a đình, or a communal house, of the village.
The most important relic of the temple is a stone epitaph erected in 1510, which was carved with legends of the god Cao Sơn, along with 39 imperial edicts of the Lê and Nguyễn dynasties.
The Western Sentry: Voi Phục Temple
Under the peaceful green canopy of Thủ Lệ Park lies Voi Phục temple, the western sentry. The temple is dedicated to Prince Hoàng Chân, the son of Emperor Lý Thái Tông. He fought against Tống invaders in the 11th century and died in the battle. To honor him, the king ordered residents to build the Voi Phục Temple, which was named after the two kneeling elephants in front of the temple.
The design of the roof is in line with the traditional style of ancient pagodas with the tail curved up to the sky, furnished with carvings of spiritual creatures like dragons, unicorns, and phoenixes, etc.
The Northern Sentry: Quán Thánh Temple
Next to West Lake is the sentry of the north: Quán Thánh Temple. Here lies the seat of the god Huyền Thiên Trấn Vũ, who is an important Taoist figure representing the North star.
As legends go, once there was a nine-tailed fox terrorizing the people. So the god Trấn Vũ came down from heaven and killed the fox. Its body sank to the ground and created West Lake as it is today; this narrative is also why the lake is sometimes called the Xác Cáo (Fox Corpse) Lake.
The temple has many invaluable relics, including around 40 wood carvings of Tang poems dating back to the 7th century. There is also a magnificent copper sculpture portraying life activities from the three interlinked worlds: Thiên (sky), Địa (earth), and Thủy (water).
Perhaps most impressive of all, however, is the four-ton, 3.96-meter black copper statue of Huyền Thiên Trấn Vũ at the main altar. According to legend, the statue presents the Taoist god precisely when he reached the highest enlightenment.
As befits a place worshiping a god of great martial power, the temple courtyard becomes a dojo in the afternoon.
More than 1,000 years have passed since the relocation of the capital, and still the legend of Tứ Trấn remains an iconic part of the city. As long as their stories are still being told, the sentries continue to stand tall to protect this land.