Mongol invasions of Vietnam

Background

By the 1250s, the Mongol Empire controlled large amounts of Eurasia including much of Eastern Europe, Anatolia, North China, Mongolia, Manchuria, Central Asia, Tibet and Southwest Asia. Möngke Khan (r. 1251–59) planned to attack the Song dynasty in South China from three directions in 1259. Therefore, he ordered the prince Kublai to pacify the Dali Kingdom. After subjugating Dali, Kublai sent one column under Uriyangkhadai to the southeast. Uriyangkhadai sent envoys to demand the submission of Đại Việt, but the Trần rulers imprisoned the Mongol envoys. This action led Uriyangkhadai and his son Aju to invade Đại Việt with 40,000 Mongols and 10,000 Yi people.

The ancestors of the Trần clan originated from the province of Fujian and later migrated to Đại Việt under Trần Kinh 陳京 (Chén Jīng), the ancestor of the Trần clan. Their descendants, the later rulers of Đại Việt who were of mixed-blooded descent later established the Tran dynasty, which ruled Vietnam (Đại Việt); despite many intermarriages between the Trần and several royal members of the Lý dynasty alongside members of their royal court as in the case of Trần Lý and Trần Thừa, some of the mixed-blooded descendants of the Trần dynasty and certain members of the clan could still speak Chinese such as when a Yuan dynasty envoy had a meeting with the Chinese-speaking Trần prince Trần Quốc Tuấn in 1282.

Professor Liam Kelley noted that people from Song dynasty China like Zhao Zhong and Xu Zongdao fled to Tran dynasty ruled Vietnam after the Mongol invasion of the Song and they helped the Tran fight against the Mongol invasion. The Tran dynasty originated from the area now known as Fujian region of modern China as did the Daoist cleric Xu Zongdao who recorded the Mongol invasion and referred to them as "Northern bandits".

A Vietnamese woman and a Chinese man were the parents of Phạm Nhan (Nguyễn Bá Linh). He fought against the Tran for the Yuan dynasty. Dong Trieu was his mother's place.

First Mongol invasion in 1258

In 1258, a Mongol column under Uriyangkhadai, the son of Subutai, invaded Đại Việt. A battle was fought in which the Vietnamese used war elephants. Aju ordered his troops to fire arrows at the elephants' feet. The animals turned in panic and caused disorder in the Đại Việt army, which was routed. The King of Đại Việt fled to an offshore island, and the Mongols occupied the capital city Thăng Long (now Hanoi). When they found their envoys in prison, one of whom died, they responded by massacring the population of the capital.

In January 29, 1258, Đại Việt's Emperor Trần Thái Tông along with Prince Trần Hoảng counterattacked at Đông Bộ Đầu (vi). The Mongols were surprised and defeated. They retreated completely from Đại Việt. According to historians, Hòe Nhai Pagoda in Ba Đình District, Hanoi, is the site of Đông Bộ Đầu where the battle took place.

The following year (1259), Uriyangkhadai returned to Đại Việt with an army of three thousand Mongols and ten thousand local troops from the conquered Kingdom of Dali, now the Yuan province of Yunnan. He led this army into Song China, and fought his way to the Yangtze River, joining with an army led by Kublai which had invaded from the north and was besieging Ezhou (modern Wuhan).

The Vietnamese had submitted unwillingly, and were reluctant vassals. The Vietnamese emperor repeatedly ignored demands to attend the Yuan court and offer his personal submission to the Great Khan. Nevertheless, according to the history of the Yuan dynasty, the Trần court sent tribute every three years and received a darughachi. By 1266, however, a standoff developed, as the Emperor Thánh Tông sought a loose tributary relationship, while Kublai demanded full submission. Trần Thánh Tông sent an official letter requiring Kublai to take his darughachi back. Because of civil war in the Mongol Empire, and the Yuan conquest of Song China, armed conflict was delayed. Instead, Kublai reminded him of the peace treaty signed by the Mongols and Đại Việt.

As a result of the Mongol conquest of the Song Empire, by 1278–79, Mongol troops reached Đại Việt's northern borders. Some former Song officials fled to Đại Việt and Champa, former vassals of Song China, during the final stage of Mongolian conquest of China. The Trầns' new ruler Nhân Tông resisted renewed Mongol demands for personal attendance at Kublai's court, but dispatched his uncle Tran Di Ai as envoy. Kublai tried to enthrone Di Ai as prince in 1281 but Di Ai and his small army were ambushed by Đại Việt forces.

Champa

Sogetu of the Jalairs, the governor of Guangzhou, was dispatched to demand the submission of Champa. Although the king of Champa accepted the status of a Mongol protectorate, his submission was unwilling. In 1282, Sogetu led a maritime invasion of Champa with 5,000 men, but could only muster 100 ships because most of the Yuan ships had been lost in the invasions of Japan.

However, Sogetu was successful in capturing Vijaya, the Champa capital later that year. The aged Champa king Indravarman V retreated out of the capital, avoiding Mongol attempts to capture him in the hills. His son would wage guerrilla warfare against the Mongols for the next few years, eventually wearing down the invaders. Stymied by the withdrawal of the Champa king, Sogetu asked reinforcements from Kublai but sailed home in 1284 just as another Mongol fleet with more than 15,000 troops under Ataqai and Arigh Khaiya reembarked on a fruitless mission to reinforce him. Sogetu presented his plan to have more troops invade Champa through Đại Việt. Kublai accepted his plan and put his son Toghan in command, with Sogetu as second in command.

Second Mongol invasion in 1285

This was the first invasion of Đại Việt by Kublai Khan's Yuan dynasty. In 1284 Kublai appointed his son Toghan (Vietnamese: Thoát Hoan) to conquer Champa. Toghan demanded from the Trần a route to Champa, which would trap the Champan army from both north and south. While Nhân Tông accept the demand reluctantly, General Hưng Đạo rallied 15,000 troops and help the Champan.

Planning to weaken the enemies first, the Đại Việt royal family abandoned the capital, letting the Mongols capture it and retreated south while enacting a scorched earth campaign by burning villages and crops. At the same time, Sogetu moved his army up north in an attempt to envelop the royal family in a pincer movement, which the Vietnamese managed to escape.

Sogetu's army was weakened by the summer heat and the lack of food, so they stopped chasing the royal family and move north to join with Toghan. Seeing the Mongol's movement, Trần Hưng Đạo concluded that the Mongol was weakened and decided to take the opportunity to strike, selecting battlefields where the Mongol cavalry could not be fully employed.

The Cham were in hot pursuit of Sogetu, however, and managed to kill him and defeat his army while it was moving north. However, according to Vietnamese history, Sogetu was defeated in Hàm Tử, Hưng Yên and was killed by the Vietnamese in his retreat. As the Yuan forces advanced down the Red River, dispersing their power, General Quang Khải counterattacked them at Chương Dương, forcing Toghan to withdraw. Toghan returned without a huge loss of the army under him thanks to the Kipchak officer Sidor and his navy. The Yuan army retreated north, but few made it back to China due to pursuing Đại Việt troops and warriors from the Hmong and Yao tribes.

The next year, Kublai installed Nhân Tông's younger brother Trần Ích Tắc, a defector to the Yuan, as prince of Đại Việt, but hardship in the Yuan's Hunan supply base aborted his plan.

Third/Final Mongol invasion, 1287-88

This was the second invasion of Đại Việt by Kublai Khan's Yuan dynasty. In 1287 the Yuan commander Toghan invaded with 70,000 regular troops, 21,000 tribal auxiliaries from Yunnan and Hainan, a 1000-man vanguard under Abachi, and 500 ships under the Muslim Omar (Vietnamese: Ô Mã Nhi) (who was the son of Nasr al-Din (Yunnan)) and Chinese Fanji (according to some sources, the Mongol force was composed of 300,000–500,000 men). Kublai sent veterans such as Arigh Khaiya, Nasir al-Din and his grandson Esen-Temür. The strategy of this invasion was different: a huge base was to be established just inland from Hải Phòng, and a large-scale naval assault mounted as well as a land attack. Despite the Mongol large-scaled invasion, Trần Quốc Tuấn confidently told the king that the invaders can be defeated easily this time. Trần Hưng Đạo withdrew from inhabited areas, leaving the Mongols with nothing to conquer. The whole fleet bringing food provisions to Toghan's army by maritime route was ambushed and destroyed by Trần Khánh Dư. Facing the lack of food again, Toghan retreated to China through the Bạch Đằng River.

Borrowing a tactic used by general Ngô Quyền in 938 to defeat an invading Chinese fleet, the Đại Việt forces drove iron-tipped stakes into the bed of the Bạch Đằng River, and then, with a small flotilla, lured the Mongol fleet into the river just as the tide was starting to ebb, while their route to the sea had been blockaded by large warships. Unable to return or escape to the sea, the entire Mongol fleet of 400 craft was caught in a bloody boarding and missile battle, sunk, captured, or burned by fire arrows. This would later become known as the Battle of Bạch Đằng (1288). The invading Mongol army of the Yuan retreated to China, harassed en route by Trần Hưng Đạo's troops. The Yuan officers such as Abachi and Fanji died in the bloody retreat and Omar was captured.

In Đại Việt

Kublai angrily banished Toghan to Yangzhou for life. The Mongols and the Tran Vietnamese agreed to exchange their war prisoners. While Nhan Tong was willing to pay tribute to the Yuan, relations again foundered on the question of attendance at the Yuan court and hostile relations continued.

The Trần Dynasty decided to accept the supremacy of the Yuan dynasty in order to avoid further conflicts. Because he refused to come in person, Kublai detained his envoy, Dao-tu Ki, in 1293. Kublai's successor Temür Khan (r.1294-1307), finally released all detained envoys, settling for a tributary relationship, which continued to the end of the Yuan.

In Champa

The Champa Kingdom decided to accept the supremacy of the Yuan dynasty as well. A tributary relationship continued for some time, but Champa disappears from Yuan records before 1300. The king of Champa made the act of vassalage to the Mongols.