among which the most important ones are the Ly Dynasty (11th and 12th century), the Tran Dynasty (13th and 14th century), the Le Dynasty (15th, 16th and 17th century) with their centralized administration, strong army forces and a highly developed economy and culture. During this period, Vietnam as a nation had to ceaselessly fought against the vicious conquering
conspiracies of Chinese and Mongolian feudal empires. Vietnam's long and tough struggles of resistance against the invasions of the Song (11th century), the Yuan or the Mongols (13th century), the Ming (15th century) had acquired glorious victories. Vietnam became stronger, all its ethnic groups became more united and the country moved into a new prosperous period after each struggle.
Dong Son culture which was enriched by the influence of Chinese culture developed from centuries to centuries in a framework of an independent state. Buddhism and Confucianism entered Dai Viet and brought with them many popular cultural features and distinct forms. Nonetheless, Vietnam still preserved its own language and a highly developed agricultural civilization.
In the 17th and 18th century, feudalism in Vietnam was considerably weakened. Peasants ceaselessly rose up in revolts that led to the Tay Son movement (1771-1802). Tay Son overthrew all regional feudal lordship that divided the country into two parts, united the country and chased away the Qing (Manchus) invaders from China, simultaneously implemented many social and cultural reforms. However, with foreign aid, Nguyen Anh soon took over the ruling power and the Nguyen Dynasty was established, which was the last royal dynasty in Vietnam.