The Trần dynasty (Vietnamese: Nhà Trần, chữ Nôm: 茹陳; Vietnamese: triều Trần, chữ Hán: 朝陳, Chinese characters: 陳朝) was a Vietnamese dynasty that ruled Đại Việt (Chữ Hán: 大越) from 1225 to 1400. The dynasty was founded when emperor Trần Thái Tông ascended to the throne after his uncle Trần Thủ Độ orchestrated the overthrow of the Lý dynasty. The Trần dynasty defeated three Mongol invasions, most notably during the decisive Battle of Bạch Đằng River in 1288. During its final decades, several succession crises and invasions from Champa severely weakened the dynasty. In 1398, emperor Trần Thuận Tông was forced to cede the throne to his three-year-old son Thiếu Đế, who in turn was forced to abdicate in 1400 in favor of the minister Hồ Quý Ly.
The Trần improved Chinese gunpowder, enabling them to expand southward to defeat and vassalize the Champa. They also started using paper money for the first time in Vietnam. The period was considered a golden age in Vietnamese language, arts, and culture. The first pieces of Chữ Nôm literature were written during this period, while the introduction of vernacular Vietnamese into the court was established, alongside Literary Chinese. This laid the foundation for the further development and solidifying of the Vietnamese language and identity.
The ancestor of the Trần clan, Trần Kinh, (陳京) migrated from the modern province of Fujian to Đại Việt during the early 12th century. He settled in Tức Mặc village (now Mỹ Lộc, Nam Định) and lived by fishing. His grandson Trần Lý (陳李; 1151–1210) became a wealthy landowner in the area. Trần Lý's grandson, Trần Cảnh, later established the Trần dynasty. From Trần Lý onwards, the Trần clan became related to the Lý clan by intermarriages with several members of the imperial Lý dynasty.
During the troubled time of many regional rebellions under the reign of emperor Lý Cao Tông, the imperial crown prince, Lý Sảm sought refuge in the territory of the Trần clan, headed by Trần Lý. During this time, the crown prince decided to marry Trấn Lý's daughter Trần Thị Dung in 1209. Afterward, it was the Trần clan who helped emperor Lý Cao Tông and crown prince Lý Sảm to restore their power and return to capital Thăng Long. As a result, the emperor appointed several members of the Trần clan to key positions in the imperial court, such as Tô Trung Từ, who was an uncle of Trần Thị Dung, and Trần Tự Khánh and Trần Thừa, who were all Trần Lý's sons. In 1211 the crown prince Lý Sảm was enthroned as Lý Huệ Tông after the death of Lý Cao Tông. By that time the Trần clan's position began to rise within the imperial court.
After a period of political crisis, the Emperor Lý Huệ Tông, who had been mentally ill for a long time, ultimately decided to pass the throne of the Lý dynasty to crown princess Lý Chiêu Hoàng in October of the lunar calendar, 1224. Ascending the throne at the age of only six, Lý Chiêu Hoàng ruled under the dominant influence of the commander of the imperial guard, Trần Thủ Độ. Even the Empress Regnant's servants were chosen by Trần Thủ Độ; one of them was his 7-year-old nephew Trần Cảnh.
When Trần Cảnh informed Trần Thủ Độ that the Empress Regnant seemed to have affection towards him, the leader of the Trần clan immediately decided to take this chance to carry out his plot to overthrow the Lý dynasty and establish a new dynasty ruled by his own clan. First Trần Thủ Độ moved the whole Trần clan to the imperial palace and arranged a secret marriage between Lý Chiêu Hoàng and Trần Cảnh there, without the appearance of any mandarin or member of the Lý imperial family. After that, he announced the fait accompli to the imperial court and made Lý Chiêu Hoàng cede the throne to her new husband on the grounds that she was incapable of holding office. Thus Trần Cảnh was chosen as her successor. As a result, the 216-year reign of the Lý dynasty was ended, and the new Trần dynasty was created on the first day of the twelfth lunar month (Gregorian: December 31) 1225.
After the collapse of the Lý Dynasty, Trần Thủ Độ was still afraid that the newly established Trần Dynasty might be overthrown by its political opponents. He therefore continued to eliminate members of the Lý imperial family: first the former emperor Lý Huệ Tông was coerced into suicide in the tenth lunar month of 1226, then other members of the Lý imperial family were massacred by the order of Trần Thủ Độ in the eighth lunar month of 1232.
Trần Thái Tông was enthroned when he was only eight years old. There were several rebellions in Đại Việt at that time, so Trần Thủ Độ had to devote all of his efforts to consolidating the rule of Thái Tông in the imperial court and over the country. Right after the coronation of the Emperor in 1226, Nguyễn Nộn and Đoàn Thượng rose in revolt in the mountainous region of Bắc Giang and Hải Dương. By both military and diplomatic measures, such as sending an army and by awarding two leaders of the revolt the title of Prince (Vương), Trần Thủ Độ was able to put down these revolts in 1229.
According to Đại Việt sử ký toàn thư, Thái Tông and his wife, the Empress Chiêu Thánh, did not have their first son for some time. This situation worried the grand chancellor Trần Thủ Độ because he had profited from similar circumstances with the Emperor Lý Huệ Tông in overthrowing the Lý dynasty. Therefore, in 1237 Trần Thủ Độ decided to force Prince Hoài Trần Liễu, Thái Tông's elder brother, to give up his wife, Princess Thuận Thiên, for the Emperor when she had been pregnant with Trần Quốc Khang for three months. After the marriage, Thuận Thiên was entitled the new empress of the Trần dynasty, while Chiêu Thánh was downgraded to princess.
Furious at losing his pregnant wife to his brother, Trần Liễu rose in revolt against the imperial family. Meanwhile, Thái Tông felt remorse about the situation and decided to become a monk at Yên Tử Mountain in Quảng Ninh in order to avoid the family feud. Finally Trần Thủ Độ forcefully yet successfully persuaded Thái Tông to return to the throne, and Trần Liễu had to surrender after judging that he could not stand with his fragile force. All soldiers who participated in this revolt were killed; Trần Thủ Độ even wanted to behead Trần Liễu, but was stopped by Thái Tông.
In 1257, the first Mongol invasion of Đại Việt was launched with the purpose of opening a southern front against the Song dynasty, whom they were fighting for more than two decades. The Mongols had already conquered parts of modern-day Sichuan and the Dali kingdom in modern-day Yunnan in order to besiege the Southern Song from the west. Trần Thái Tông opposed the encroachment of a foreign army across his territory and so dispatched soldiers on elephants to deter the Mongol troops. The elephant-mounted troops were routed by sharpshooters targeting the elephants. In comparison with the previous Ly dynasty, the Tran had strengthened their armed forces and were able to deter the Mongol attacks.
At the beginning of the war, the Đại Việt army suffered several defeats at the hands of an overwhelming force that had already conquered a vast area in Asia. Several high-ranking officials of the Trần dynasty were so fearful that Prince Trần Nhật Hiệu, the younger brother of Thái Tông, even suggested to the Emperor that they might escape from Đại Việt to the Song dynasty.
Trần Thái Tông submitted to the Mongols after the loss of a prince and the capital. In 1258, the Trần commenced regular diplomatic relations and a tributary relationship with the Mongol court, treating them as equals to the embattled Southern Song dynasty without renouncing their ties to the Song.
Kublai Khan was dissatisfied with the arrangement at the end of the first invasion and requested greater tributary payments, including taxes to the Mongols in both money and labor, "incense, gold, silver, cinnabar, agarwood, sandalwood, ivory, tortoiseshell, pearls, rhinoceros horn, silk floss, and porcelain cups", and direct oversight from a Mongol-appointed darughachi. In 1283, Khubilai Khan sent word to the Trần that he intended to send Yuan armies through Trần territory to attack the kingdom of Champa, with demands for provisions and other support to the Yuan army.