The Ly Dynasty was in power for 215 years. Although, the aggressors did not invade Thang Long, but the capital saw some royal riots and wars between parties. The citadel was fired many times, forcing the Ly King to set up a thatched cottage near To Lich River to live. In 1226, the Tran Dynasty replaced the Ly and stopped the chaotic time, re-establishing the social order. Inheriting achievements in the country construction of the Ly Dynasty, the Tran Dynasty had many policies and active measures to boost economic and defense development, improving local people’s living condition as well as keeping Dai Viet’s independence.
In 1230, the Tran Dynasty upgraded Dai La Citadel, re-zoning administrative units and dividing it into 61 wards. Thien An Palace was where the King worked and held parties with officials. Tap Hien and Tho Quang Palaces were used for meeting envoys. Dien Hong Palace was where the elders’ meeting took place in the fight against the Nguyen-Mong invader. Besides Hoang Thanh, the Tran Dynasty built Quan Su zone (near the current Quan Su Pagoda) to welcome the envoys. Thang Long had the honor to be the land where was home to many bonzes and researches specializing in Buddhist studies such as Tran Thai Tong, Tue Trung Thuong Si, Tran Thanh Tong and Tran Nhan Tong. Tran Thai Tong was the first in the Tran Dynasty and was also a person who set a good example for studying Buddhist studies of the Tran royal dynasty. The following heroic kings of the Tran dynasty, notably Tran Nhan Tong, were faithful Buddhists who had comprehensive researches on Buddhist studies and exploited active elements of the Buddhism in the construction and protection of the nation. Therefore, Buddhism in the Tran Dynasty had many active elements: entering the world, non-scholastic, non-resentment and having militant spirit of the national and the sake of local people. All of these brought Buddhism distinguished features of the Vietnamese nation.
In terms of culture, Thang Long Citadel was an open city, containing cultural quintessence of many countries but still maintaining its national cultural identities. Confucianism in the Tran Dynasty won the domination and Confucianism education was appreciated and developed. From 1247, the Tran Dynasty had additional diplomats called Trang Nguyen (the first doctoral candidate), Bang Nhan (the second in doctoral examination) and Tham Hoa (the third in doctoral examination). An important factor to form Dai Viet culture in the Tran Dynasty, or in other words, contributing to creating Dong A Sprit which was the Tran Dynasty’s science of war. Tran Quoc Tuan compiled Elementary military manual (Binh thu yeu luoc) and book Van kiep binh thu which were foundations for training military mandarins. In the Tran Dynasty, the spirit of appreciating martial arts and literature were a source of strong inspiration for many writers and poets. It encouraged the appearance of many big writers like Han Thuyen, and Nguyen Si Co and educator Chu Van An. Tran Nhan Tong, Tran Quang Khai, Truong Han Sieu and Pham Su Manh were famous poets of patriotic literature. Le Van Huu was a wise historian who wrote the Annals of Dai Viet or Dai Viet Su Ky.