In the 10th century AD, the Vietnamese had won their freedom and built up an independent state named Dai Viet. The country was under the ruling of many national feudal dynasties, 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, Tours In Vietnam as a nation had to ceaselessly fought against the vicious conquering conspiracies of Chinese and Mongolian feudal empires. Tours In 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. Tours In Vietnam became stronger, all its ethnic groups became more united and the country moved into a new prosperous period after each struggle.