Tây Sơn is the name given to three brothers, Huệ, Lữ and Nhạc, of the clan of Hồ, which take part in the civil war Vietnamese at the end of the 18th century.

Originating in Tây Sơn (from where their name), a village located close to Which Nhơn, they revolt in 1771 against the lords of the South, the Nguyễn. Helped by the Trịnh, lords of North and rivals of the latter, they take initially the town of Which Nhơn, which becomes their capital, then of Gia Ðình (current Saigon) and finally of the capital, Huế. The Nguyễn family members all are killed, except for young prince Ánh, 16 years old, nephew of the last Nguyễn lord, who takes refuge in the delta of the Mekong, then obtains the support of the French via the prelate Pierre Pigneau de Béhaine.

Under the name of Quang Trung, Huệ -   who as his brothers changed his family name, Hồ, for that of Nguyễn  - proclaims emperor in 1788, putting fine in fact at the theoretical reign of the dynasty It, like with the domination of Trịnh in north. In 1789, they push back the Chinese, called for the aid by It, with the Bataille of Đống Đa. In 1792, Quang Trung dies without heir, thus starting a war of factions within the partisans of Tây Sơn. The disorder makes it possible to prince Ánh to reconquer the south, held by Lữ, the least qualified last and of the three brothers.

Their dynasty ends in 1802, when Nguyễn Phúc Ánh proclaims emperor under the name of Long Gia.

A school D martial arts which takes its origins of Tay Son.