Tây Sơn (西山): the history behind the name

The name of Tây Sơn (西山) is used in many ways to refer to the period of peasant rebellions and decentralized dynasties established between the eras of the Later Lê and Nguyễn dynasties in the history of Vietnam between 1770 and 1802. The name Tây Sơn is used to refer to the leaders of this revolt (the Tây Sơn brothers), their uprising (the Tây Sơn Uprising) or their rule (the Tây Sơn Dynasty or Nguyễn Tây Sơn Dynasty).^[1]

Emperial Seal

Nguyễn Huệ was the second eldest of three brothers from the village of Tay Son in An Khe District, Nghia Binh Province in Central Vietnam. He was the most talented and famous among the three brothers and took the name Quang Trung when he proclaimed himself as Emperor. He distributed land to poor peasants, encouraged hitherto suppressed artisans, allowed religious freedom, re-opened Vietnam to international trade, and replaced Chinese with Vietnamese written script called Chữ Nôm, as the official language.

Despite the short reign of less than 4 years (1788-92), he has remained the most well-known and revered by vietnamese people for his genius military and administrative skills. His victory over the Chinese invasion is still celebrated yearly in Vietnam as the Dong Da citadel victory, in which he was able to recruit and trained 100,000 men in less than a month and repelled the Chinese invasion force of 200,000 men out of North Vietnam in less than a week.

The ambitious character of Quang Trung is legendary in Vietnamese history. He ordered the melting of Vietnamese coins to make cannons, and hoped to "restore" the Chinese provinces of Guangxi and Guangdong to Vietnamese sovereignty. Several stories tell of his ambitious plans and indirect challenge to Qian Long. Quang Trung even proposed to marry one of Qian Long's daughters, an indication of his intention to claim Chinese territory.

In early 1792, Quang Trung planned the final assault on the remaining base of Nguyễn Ánh's around Saigon, both by sea and land. While waiting for the seasonal winds to change direction into a tailwind to propel his navy, he suddenly collapsed and died of unknown causes at the age of 40. Many Vietnamese believe that if he had ruled for another ten years, the fate of the country would have been significantly different.

Sources from Wikipedia: Tây Sơn Dynasty and from Quang Trung/Nguyen Hue