Đại Việt was Vietnam’s official royal name for centuries
From the tenth century into the early nineteenth, Vietnamese monarchies centered near modern Hanoi styled themselves Đại Việt—Great Việt. Đinh Bộ Lĩnh adopted the related name Đại Cồ Việt in 968 after reunifying the realm. Eight dynasties later wore the title through rise, fracture and brief foreign interruption.
Before independence, what is now northern Vietnam spent about a thousand years under a string of Chinese dynasties, known in turn as Nanyue, Jiaozhi, Jiaozhou, Annan and Jinghai Circuit. The word Việt itself came from Chinese Yue, a label once applied to many non-Han peoples of the south; ancestors of today's Kinh borrowed it during the late Tang era and made it their own. That long rule left marks still visible, including Chinese-derived scripts used for Vietnamese, Tày and Nùng.
When Đinh Bộ Lĩnh proclaimed himself emperor in 966, he called his state Đại Cồ Việt, probably a Sino-Vietnamese prefix for great attached to a local word. The Japanese historian Momoki Shiro has suggested that form may be a copying error or a later invention. Bricks from Hoa Lư, the first capital, already carry the phrase Đại Việt Quốc in the tenth century, and in 1054 Lý Nhật Tôn formally dropped the Cồ.
The early state was a hereditary monarchy with Mahayana Buddhism as its official faith. Power passed from the Đinh to the Early Lê, then to the long-lived Lý (1009–1226) and Trần (1226–1400). The Hồ briefly renamed the country Đại Ngu, and from 1407 to 1427 Ming China ran it again as Jiaozhi before the Later Lê restored independence.
Unity lasted until 1533. After that, the Lê, Mạc, Trịnh and Nguyễn families governed rival domains at the same time, a period of civil conflict that ran from the Lê–Mạc struggle through the long Trịnh–Nguyễn standoff to the Tây Sơn uprisings. The Tây Sơn brothers reunited the land in 1786 only to split it among themselves a year later. Meanwhile the state pushed south and west into Champa and Cambodian territory until its borders came to resemble modern Vietnam. The Nguyễn clan finally crushed the Tây Sơn and founded a new dynasty in 1802, closing 262 years of division.
Source: Đại Việt