|History of Vietnam
Đại Việt (大越, IPA: [ɗâjˀ vìət], literally Great Viet) is the name of Vietnam for the periods from 1054 to 1400 and 1428 to 1804. Beginning with the rule of Lý Thánh Tông (r. 1054–1072), the third emperor of the Lý Dynasty, until the rule of Gia Long (r. 1802–1820), the first emperor of the Nguyễn Dynasty, it was the second-longest used name for the country after "Văn Lang".
Beginning with the rule of Đinh Tiên Hoàng (r. 968–979), the country had been referred to officially as Đại Cồ Việt (大瞿越); cồ (瞿) in the name of Gautama Buddha (瞿曇·喬達摩). The term "Việt" is the same as the Chinese word "Yue", a name in ancient times of various non-Chinese groups who lived in what is now northern/southern China and northern Vietnam; the full name means "Great Buddhist Viet". In 1010 Lý Thái Tổ, founder of the Lý Dynasty, issued the "Edict on the Transfer of the Capital" and moved the capital of Đại Cồ Việt to Thăng Long (Hanoi) and built the Imperial Citadel of Thăng Long where the Hanoi Citadel would later stand.
Dai Viet is a strategic location. By invading Dai Viet, the Mongols would be able to bypass the Himalaya and drive deep into South East Asia. However, the Mongolians of the Yuan Dynasty invaded Dai Viet three times and were defeated. The last battle, the Battle of Bach Dang, was a decisive defeat for the Mongolians. Dai Viet's perseverance thrwarted Mongolian attempts to conquer South East Asia and prevented the fourth Mongolian invasion of Japan, as the Mongol navy was completely destroyed during Bach Dang. This became one the greatest victories in Vietnamese military history.
In 1400, the founder of the Hồ dynasty, Hồ Quý Ly usurped the throne and changed the country's name to "Đại Ngu" (大虞). 7 years later, in 1407, Vietnam fell under Ming dynasty domination, which lasted for 20 years until 1427. The Ming renamed the area "Jiaozhi". In 1428, Lê Lợi, the founder of the Lê dynasty, liberated Jiaozhi and restored the kingdom of "Đại Việt".