Place
Co Loa
A three-ringed citadel north of today's Hanoi, its outer rampart running some eight kilometres. The old histories call it Snail Citadel for its spiral shape; the name Co Loa appears only in a later gloss.
At a glance
- Also known as
- Snail Citadel — the old history explains the name by its spiral shape; also called Tu Long; the Tang called it Con Lon, meaning a very high citadel1
- Location
- North of Hanoi, on the Red River delta. The ditches outside the ramparts may once have been moats feeding a reservoir inside, which drew water from the Hoang river, itself joined to the Red River2
- Type
- An earthen citadel of three circuits, with ditches outside the ramparts and added mounds and towers2
- Area
- The inner circuit is near rectangular, 1,650 m around, its wall about 5 m high, 6–12 m across the top and 20–30 m at the base. The middle circuit runs about 6.5 km, in places some 20 m wide and up to 10 m high. The outer circuit runs about 8 km, with stretches still 3–4 m high and 12–20 m thick2
- Dates
- A section through the rampart shows five building phases in three periods: the earliest in the fourth century BC or later, the next in the third century BC or later, and a repair in the fifteenth or sixteenth century AD3
- Excavated
- In 1970 a collapsed stretch of the outer rampart was examined; in 2004 and 2005 the Institute of Archaeology dug inside the inner circuit; the Vietnamese-American team published its peer-reviewed report in 20103
About the place
The old chronicles say
The oldest text describes the citadel by an image rather than by measurement: the king raised a wall at Viet Thuong, a thousand truong across, coiling like a snail, and so it was called the Snail Citadel. Another book quoted in the notes says it went round nine times. The snail is right — the circuits wind unevenly, neither square nor round — but the number is not: there are three. That error is itself informative: the fifteenth-century historian was describing the place from hearsay, not from survey.1
Archaeology finds
Archaeology cannot answer whether this citadel was An Duong Vuong's — earth records no owner's name. It answers a different question: when it was raised, and how many times. The main rampart of the middle circuit was built in the closing centuries BC, before the Han arrived, and it was not the first line of defence on the spot. That dating overlaps the span the old histories give An Duong Vuong: it does not prove him, and does not exclude him either. The authors write that the material evidence supports the possibility of an Au Lac polity without demonstrating it conclusively, and raise another possibility — that Nam Viet, after its conquest around the start of the second century BC, may have been the power that added to the walls.4
What has been dug up inside sketches a place that farmed, cast bronze and prepared for war at once. The earliest layer in the inner circuit yielded kilns, bricks, moulded tiles and stone moulds for casting bronze arrowheads; charcoal from a rubbish pit beside an arrowhead kiln returned a radiocarbon date of 2,190 years before the present, give or take 35 years. Five hundred metres from the south-east corner of the inner circuit came the Co Loa drum, 72 kg in weight, the largest found in the region, holding some 200 bronze objects including 96 ploughshares. At Cau Vuc just outside the south gate lay a hoard of about ten thousand socketed bronze arrowheads.5
In 1970, at a collapsed stretch of the outer rampart, Dong Son pottery was found lying in a layer beneath the body of the wall. People had lived on the spot before the wall existed, and the wall was raised over the traces of their daily life.3
How later ages remembered
The citadel's value, for O'Harrow, lies not in its size but in what that size demands: the local economy had to produce an agricultural surplus and pull people off the land, and to finish the work in a relatively short span of time. The 2010 team supplies the other half: the labour required for so unprecedented a work must have called for a strong military and centralised, state-like control.64
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