It was told that King An Duong has a secret weapon which was the magic crossbow (given to him by a golden tortoise) that help him fight against the enemy. However, his daughter My Chau told her father’s secret to her husband Trong Thuy, son of rebel Chinese general Trieu Da and thereby unwittingly allowed Trieu Da to conquer Co Loa in 208 BC. King An Duong later found out the reason of his failure, he decided to kill My Chau and then killed himself afterward.

The festival is formally started on the 6^th day of the New lunar year with a possession of notables from surrounding villages to the King An Duong Temple where a miniature royal court containing an incense burner; a stone tablet and a funeral oration is placed in front of the two altars; a ceremony then takes places in the king’s honor, accompanied by the traditional music. Then, the possession will continue going to the Trong Thuy well and back to the various hamlets, accompanied by fire – crackers. The festival continues until the 15th day of the first lunar month, with evening fireworks displays, traditional games such as cock fighting, chess, tug of war, wrestling, swing, rope climbing, martial arts, flag dancing and archery and performances of ca trù, chèo and tuồng.

Cổ Loa Citadel in Hà Nội Capital City, Vietnam{itpsharepoint}