The Ô Diên Citadel in Đan Phượng district is much less famous than the other ancient capitals of Thăng Long and Huế.
At the end of the 6thcentury AD, Vietnam (not yet named as such) resisted invasions by the Chinese Liang and Sui dynasties.
In the spring of 542, a general uprising led by national hero Lý Bí overthrew their Chinese Liang rulers. In April 542 and 543, Lý Bí thwarted the Chinese attempts to reclaim their former conquest.
In spring 544, LýBí declared the country’s independence in the name of Vạn Xuân as a symbol of longevity, literally translated as “Ten Thousand Springs”. He crowned himself Nam Đế (King of the Southern land).
In 545, however, the Chinese mounted their largest ever attack, forcing Lý Bí to flee to the safety of the highlands and transferring his power to General Triệu Quang Phục.
Lý Bí’s elder brother Lý Thiên Bảo withdrew to a Laotian border area while General Triệu Quang Phục continued to fight the Chinese aggressors in the Northern Delta.
Triệu Quang Phục successfully expelled the Chinese invaders in 550 and declared himself Triệu Việt Vương (King Triệu of the Việt land).
Lý Thiên Bảo died in 555, his forces taken over by kinsman Lý Phật Tử. Two years later, Lý Phật Tử launched an attack against Triệu Việt Vương. Lý Phật Tử based his capital in Ô Diên from 557 until 602. History recorded his government as the Hậu Lý Nam Đế Dynasty. In 571, Lý Phật Tử defeated Triệu Việt Vương, becoming ruler over the whole country.
The Chinese Sui Dynasty asked Lý Phật Tử to submit to its rule in 602, but its demand was rejected. He moved the capital to Cổ Loa and devised defence plans. He ordered his nephew Lý Đại Quyền to deploy troops to protect the Long Biên citadel (now Bắc Ninh Province) and asked General Lý Phổ Đỉnh to defend the former capital Ô Diên.
After numerous bloody battles, the Lý Phật Tử was forced to surrender. His generals went on fighting bravely but were all killed. The country was then ruled by the Sui Dynasty.
Against all odds leading to its final doom Lý Phật Tử’s dynasty was an important historical era in the founding of Vietnam, with Ô Diên Citadel-the first capital of the post-Lý Nam Đế dynasty- recognised as one of Hanoi’s most precious relics dating back long before the Thăng Long Capital Era.
At a recent seminar leading historians and researchers confirmed the Ô Diên Citadel’s role as a political and military centre at the end of the 6th century.
History Professor Lê Văn Lan said the country’s first capital city was Văn Lang, the second Cổ Loa, and the third Hoa Lư.
“The time between the second and third capitals was a thousand year period littered withVietnamese resistance battles against Chinese domination. It is clear that during this historical period, Ô Diên was a capital of the court from 571 to 602.”
Hạ Mỗ Commune Culture Chamber Chief Nguyễn Xuân Việt said the commune boasts an impressive string of historical relics.
“After 15 centuries, the traces of the Ô Diên political and military centre can only be seen in ancient structures like Vạn Xuân Communal House, Hàm Rồng Temple, Chính Khí Temple and Văn Hiến Temple,” Việt added.
Local folklorist Nguyễn Tọa underscored that generations of commune residents have upheld the tradition of patriotism, national independence, and indomitable struggle in the intervening years.
"We locals worship historical personages including Lý Phật Tử, his sons Lý Bát Lang and Lý Nhã Lang, and General Lý Phổ Đỉnh.”
“We still remember old verses like: ‘Our village was the former home of a King/ Our people were once ruling mandarins/ This land has served as a national capital/We preserve this history of loyalty’,” said Tọa.
Hạ Mỗ was the birthplace of many prominent figures. For instance, Tô Hiến Thành (1102–1179), a man famous for his skill in both literature and martial arts, became a leading mandarin in the later 12th century Lý Dynasty. In the 19thcentury, the monk Thích Thanh Trang from Hải Giác Pagoda led an uprising against the French. He was executed by the colonisers at the village.
The story of the ancient Ô Diên Citadel remains fresh in the minds of village elders particularly with the procession that removed a statute from a temple dedicated to Lý Phật Tử to the village’s communal house.
He said Folklorist Tọa and cultural researcher Việt accompanied us while we were touring Hạ Mỗ main historical relics.
“After the country’s independence was declared by King Lý Nam Đế, Vạn Xuân Communal House took shape to worship Prince Lý Bát Lang and was officially recognised as a national historical relic in 1991,” said Việt.
The communal house contains a stele reading: King Lý Phật Tử assigned locals to build a temple for his son Lý Bát Lang, on his palace’sfoundation, after the Prince died. This is Hàm Rồng Temple.
Hạ Mỗ’s Chính Khí Temple is dedicated to King Lý Phật Tử, Văn Hiến Temple toTô Hiến Thành, and Tri Chỉ Temple to General Trần Hưng Đạo who defeated the Yuan Dynasty’s Mongol invaders on three times in the 13th century.
He said most of the ancient Han script parallel sentences adorning local temples and pagodas relate to Ô Diên.
“Most of Hạ Mỗ’s communal houses, pagodas, and temples—as well as local festivals bear the traces of the Ô Diên Citadel’s ancient glory,” he added.