TL;DR: Old histories record that An Dương Vương, surnamed Thục and named Phán, founded the state of Âu Lạc, established his capital at Phong Khê and built Loa thành. The legend of the magic crossbow and of Mị Châu and Trọng Thủy explains the defeat at the hands of Triệu Đà. Modern scholars regard this as a legendary layer reflecting an ancient state in the North of Vietnam, not a historical record accurate in every detail.
Who was An Dương Vương and how did the state of Âu Lạc come into being?
An Dương Vương is the figure recorded in old histories as king of the state of Âu Lạc, who founded the kingdom after defeating the eighteenth Hùng Vương, established his capital at Phong Khê and had Loa Citadel built. The book *Việt Nam sử lược* (Trần Trọng Kim, 1920) records that in the year Giáp Thìn (257 BCE; the printed book mistakenly has 275), after pacifying all regions, the Thục lord proclaimed himself An Dương Vương, changed the state name to Âu Lạc, and set his capital at Phong Khê (the book's gloss: in Đông Anh district, Phúc An province; today the Cổ Loa area of Hà Nội); two years later, in the year Bính Ngọ (255 BCE), An Dương Vương built Loa Citadel[1].
According to the old histories, the Thục lord once proposed marriage to Mị Nương, daughter of the eighteenth Hùng Vương, but was refused, and so harboured a grudge, instructing his descendants to later attack and take the state of Văn Lang to avenge this insult. At that time the Hùng Vương, believing himself to have strong troops and good generals, neglected state affairs and indulged only in wine. Seizing the situation, a nephew of the Thục lord named Phán led troops to attack and captured the state of Văn Lang. The Hùng Vương, defeated and fleeing, jumped into a well and took his own life[1].
However, Nguyễn dynasty historians and later researchers have raised questions about the origin of the Thục lineage. Trần Trọng Kim states clearly that the Thục house recorded in our histories is not the state of Thục in China, since Chinese histories indicate that at that time the land of Ba Thục (Sichuan) was already under the rule of the Qin, so there was no longer a king there. He also cites the *Khâm định Việt sử* with a similar argument, and offers the opinion that Thục was in fact some independent lineage near the state of Văn Lang, not the Thục of China[1].
How did the Qin attack on the Hundred Yue and the regional context unfold?
Việt Nam sử lược records that while An Dương Vương was king of Âu Lạc, Qin Shi Huang had unified China. In the year Đinh Hợi (214 BCE), Shi Huang sent the general Đồ Thư with troops to take the land of the Hundred Yue (the book's gloss: roughly the present provinces of Hunan, Guangdong and Guangxi). Also according to this book, An Dương Vương offered allegiance to the Qin, and the Qin divided the land of the Hundred Yue together with the land of Âu Lạc into three commanderies: Nam Hải (Guangdong), Quế Lâm (Guangxi) and Tượng quận (glossed in the book as northern Vietnam)[1].
The book continues: the native people of the Hundred Yue lands would not submit to rule by the Qin officials and troops and fled into the forests. Before long the troops of Đồ Thư, who came from the north, could not bear the climate and many fell ill. The Hundred Yue seized the moment, rose up and killed Đồ Thư[1].
Still according to Việt Nam sử lược, the Qin later weakened and its realm fell into disorder. In Nam Hải commandery, the commandant Nhâm Ngao saw his opportunity and plotted to seize Âu Lạc in order to establish an autonomous state in the south. But before the plan could succeed, Nhâm Ngao died. On his deathbed, Nhâm Ngao handed military authority to Triệu Đà, so that Triệu Đà took his place as commandant of Nam Hải commandery. In the year Quý Tị (208 BCE), the fiftieth year of An Dương Vương's reign, Triệu Đà led troops to seize Âu Lạc and founded the state of Nam Việt[1].
The legend of the magic crossbow and Cổ Loa Citadel: what is historical record and what is myth?
According to *Đại Việt sử ký toàn thư* (in the 1945 translation by Mạc Bảo Thần, or Nhượng Tống), the citadel collapsed each time it was finished, so the king fasted and prayed to heaven, earth and the spirits of mountains and rivers. In the third month of the year Bính Ngọ a spirit came to the gate and told him to wait for the River Envoy; the next morning a golden turtle came swimming up the river, called itself the River Envoy, and showed the king how to destroy the evil essence hiding in Thất Diệu mountain and to kill the white rooster at the inn beside the mountain, after which the citadel was finished in less than half a month. On leaving, the golden turtle pulled off a claw and gave it to the king, telling him to use it as a crossbow trigger and shoot when enemies came[2].
Also according to *Đại Việt sử ký toàn thư*, the king ordered his minister Cao Lỗ (some books record Cao Thông) to make the magic crossbow, using the claw as the trigger, called the sacred shining magic crossbow, the golden claw[2].
Trần Trọng Kim recounts a similar legend: when An Dương Vương was building Loa Citadel, evil spirits harassed the work so that construction could never be completed. The king set up an altar and prayed, and the Kim Quy spirit appeared and showed him how to expel the evil spirits, thanks to which the citadel was finally completed. The Kim Quy spirit also gave the king a claw to serve as the trigger of a crossbow. Whenever there was an enemy, the king would bring out the crossbow and shoot once, and the enemy died by the tens of thousands. It was thanks to this crossbow that Triệu Đà could not defeat An Dương Vương[1].
The Toàn thư continues: Triệu Đà knew that the king had a magic crossbow and that he was no match for it, so he withdrew to hold Vũ Ninh mountain and sent envoys to sue for peace. The king was pleased and divided the land at Bình Giang (glossed in the book as the Thiên Đức river in Đông Ngàn): north of it Đà would govern, south of it the king. Đà sent his son Trọng Thủy to serve as a guard and asked to marry the king's daughter Mỵ Châu. The king agreed. Trọng Thủy coaxed Mỵ Châu into letting him see the sacred crossbow in secret, stealthily ruined the trigger and replaced it, then, on the pretext of going north to visit his parents, told Mỵ Châu that the love between husband and wife could never be forgotten[2].
Trọng Thủy asked Mỵ Châu: what talent does Âu Lạc have that no one can defeat it? Mỵ Châu told him about the crossbow and showed it to her husband. Trọng Thủy then took the Kim Quy claw and replaced it with a false trigger, then intended to return to inform his father. As he was about to leave, Trọng Thủy asked Mỵ Châu: if there were an enemy attack and pursuit, how would he know where to find her? Mỵ Châu told him that she had a goose-feather cloak, and if she fled anywhere she would scatter those feathers along the road so he would know. The book goes on: Triệu Đà raised his army, the crossbow no longer worked, and An Dương Vương put Mỵ Châu on his horse and fled south to Mộ Dạ mountain; the Kim Quy spirit appeared and said the enemy was sitting behind the king, whereupon the king cut down Mỵ Châu and threw himself into the sea[1].
What are the differences between the historical sources?
The two books disagree on many details. On the last Hùng Vương, *Việt Nam sử lược* has him flee in defeat and throw himself into a well[1]; *Đại Việt sử ký toàn thư* only says he was still drunk when his soldiers turned their spears and surrendered[2]. On the end of An Dương Vương, *Việt Nam sử lược* has him throw himself into the sea[1], while the Toàn thư has him walk into the sea holding a seven-inch rhinoceros horn[2]. Ngô Sĩ Liên himself doubts the tale in his commentary: he writes that the goose feathers marking the road "may well never have happened", and that the story of losing the kingdom because the crossbow trigger was swapped was made up to make the object seem sacred[2].
On the origin of the Thục lineage, the Toàn thư records An Dương Vương as surnamed Thục, personal name Phán, a man of the state of Ba Thục[2]; Trần Trọng Kim rejects this and cites the *Khâm định Việt sử* to argue that Thục was not the state of Thục in Sichuan[1]. This is a view shared by many later researchers, though opinions still differ on the specific identification of who the Thục house was.
On chronology, both books place An Dương Vương's first year in the year Giáp Thìn and both give him a fifty-year reign, down to the year Quý Tỵ[1][2]. The discrepancy lies in the conversion to Western dates: *Việt Nam sử lược* gives the Thục house as 257 to 207 BCE, with the year Đinh Hợi as 214 and the year Quý Tỵ as 208[1], while the 1945 translator of the Toàn thư glosses Đinh Hợi as 216 and Quý Tỵ as 210 BCE[2]. The absolute dates of this period should therefore be taken as the figures of the old histories, not as verified dates.
What are the Cổ Loa relics and archaeological value?
According to *Việt Nam sử lược*, Loa Citadel was of great height and spiralled inward like a snail shell from the outside, which is why it was called Loa Citadel. Traces remain today in Cổ Loa village, Đông Anh district (before July 2025), Hà Nội[1].
The Cổ Loa site today is one of Vietnam's most important archaeological sites, with a system of ramparts remaining from many periods. Archaeologists have discovered many artefacts of the Đông Sơn culture here, helping to clarify the historical context of the period believed to be the state of Âu Lạc.
However, determining precisely the date of the citadel's construction and its direct connection with the figure of An Dương Vương remains a matter under study, with no fully agreed conclusion among archaeologists and historians.
What is the conclusion on An Dương Vương and Âu Lạc?
An Dương Vương and the state of Âu Lạc are a subject at the intersection of historical record and legend. The great histories such as *Đại Việt sử ký toàn thư* and *Việt Nam sử lược* both record this figure, but the sources themselves contain many legendary layers such as the magic crossbow, the Kim Quy spirit, Mị Châu and Trọng Thủy. Modern researchers approach the subject by separating the historical layer from the mythical layer, while cross-checking with archaeological evidence at the Cổ Loa site.
