|History of Vietnam
i Vi?t (, IPA: [?âj? vì?t], literally Great Viet) is the name of Vietnam for the periods from 1054 to 1400 and from 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 Nguy?n Dynasty, it was the second-longest used name for the country after "V?n Lang".
Beginning with the rule of ?inh Tiên Hoàng (r. 968-979), the country had been referred to officially as i C? Vi?t (). The term "Vi?t" 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. In 1010 Lý Thái T?, founder of the Lý Dynasty, issued the "Edict on the Transfer of the Capital" and moved the capital of i C? Vi?t to Th?ng Long (Hanoi) and built the Imperial Citadel of Th?ng 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 thwarted Mongolian attempts to conquer South East Asia and prevented the third 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 H? dynasty, H? Quý Ly usurped the throne and changed the country's name to "i Ngu" (), but his dynasty was overthrown by the invading Ming Empire who annexed i Ngu in 1407 for 20 years until 1427. The Ming renamed the area "Giao Ch? (or Jiaozhi)". In 1428, Lê L?i, the founder of the Lê dynasty, liberated Giao Ch? and restored the kingdom of "i Vi?t".