Thái people (Vietnam)
[1] They centered in the valley of Muang Thaeng (today's Điện Biên Phủ), a place strongly connected to the legend of Khun Borom.By the 11th century, the Vietnamese chronicle Đại Việt sử lược recorded the Black Thai had formed a polity in Sơn La called Ngưu Hống (Chinese: Heishui).A number of these mueang in the region grouped together and formed a long-term alliance, called Sip Song Chau Tai (Twelve Lands of Thai).This federation of Sip Song Chau Tai maintained political autonomy and had tributary relationship with the regional powers, such as China, Lan Xang, Siam and the dynasties of Vietnam.This was arranged by the French explorer and colonial representative Auguste Pavie who signed a treaty with Đèo Văn Trị, the White Thai lord of Muang Lay (Lai Châu) on 7 April 1889.