Archaeologists have recently discovered traces of a form of rampart beneath the spiral-shaped Co Loa Citadel, an ancient walled city, in Hanoi’s Dong Anh district.

The information was released at a recent conference in Hanoi announcing research findings on the Co Loa Citadel since 2007.

Co Loa, the biggest and most ancient citadel found in Vietnam , was built by King An Duong Vuong between 214 and 208 BC as the capital of Au Lac, one of the earliest Vietnamese kingdoms.

It is believed to be comprised of nine concentric circles, yet only vestiges of three circles can be found at present. They include an 8km exterior wall, a 6.5km polygon-shaped inner wall, and a central 1.6km rectangular wall.

The newly uncovered citadel lies underneath Co Loa’s inner wall and belonged to the Dong Son Civilisation (dating from 1,000 BC to 100 AD), Dr Trinh Hoang Hiep from the Vietnam Institute of Archaeology said, adding that experts have yet found out its specific shape and size.

Archaeologists came to a conclusion that King An Duong Vuong built his Co Loa Citadel on the basis of this structure, he noted.

At the conference, they also proposed an area typical for the Co Loa relic site to be recovered and opened to the public.

The site was recognised as a national special relic in 2012.-VNA