Tran Du Tong

As emperor Thiệu Phong era From 1341 to his death in 1357, the Senior Emperor Minh Tông acted as a regent for his son Dụ Tông, who thus reigned only in name. According to Đại Việt sử ký toàn thư, the young Emperor Dụ Tông was very intelligent and was completely focused on managing both civil and military matters of Đại Việt. For that reason, Dụ Tông in his first era Thiệu Phong (1341–1357) was well respected in the royal court even if it was the Senior Emperor who ruled the country.

In this era, the royal court of Trần Dynasty began to face troubles such as the death of several important and experienced mandarins, the failure of some military campaigns against Lan Xang and Champa and the proliferation of many natural disasters in Đại Việt.

In 1353, Minh Tong attempted an expedition against the Champa king Tra Hoa Bo De in support of Che Mo's claim to the throne as the son of Che Anan. The expedition was aborted and Che Mo died soon after.

Đại Trị era After the death of Minh Tông in 1357, Dụ Tông ascended to the throne and he decided to change the era from Thiệu Phong to Đại Trị (1358–1369). With the death of a capable ruler like Minh Tông, the royal court led by Dụ Tông began to fall into chaos, especially as several able officials such as Nguyễn Trung Ngạn and Trương Hán Siêu died while others such as Chu Văn An became discontented. After the Emperor's refusal of his famous Thất trảm sớ (Petition of beheading seven corrupt officials), Chu Văn An decided to leave the royal court, which was now full of corrupt mandarins and bad cohorts.

At that time, the situation in China was very complicated with the struggle between Zhu Yuanzhang and Chen Youliang, both of whom tried to mobilise support from Đại Việt. However, Dụ Tông maintained a neutral attitude to concentrate his army along the southern border against Champa. Despite his effort, Champa's forces still posed concerns for Đại Việt's border and launched several skirmishes while many revolts were taking place and causing diversions in Đại Việt. Dụ Tông introduced theatre, which was considered at the time to be a shameful pleasure, in the royal court. The Emperor died on 25 May of the Lunar calendar, 1369, at the age of 33 following a reign of twenty-eight years. He did not have any posthumous name and was buried in Phụ Tomb. Being impotent, Dụ Tông had no son of his own and before his death, he issued an edict that the throne would be passed to Dương Nhật Lễ despite the fact that his appointee was not from Trần clan while the royal family still had several capable princes available for the position. This decision of Dụ Tông was heavily criticized by imperial historians because it broke the normal protocol for succession and heralded the start of a chaotic period of the Trần Dynasty.