Khun Borom is the ancestral culture hero of the Lao and the wider Tai-speaking world. In the Nithan Khun Borom, the Lao chronicle of origins, the sky king Phaya Thaen sends him down after a great flood to reign at Mueang Thaen, the plain of Dien Bien Phu; most redactions make him the sky king's own son. During his reign two vast gourds sprang up, and when they were pierced the peoples of the land — the aboriginal inhabitants first, then the Tai-Lao — poured out of them, making Khun Borom the sovereign of a repopulated world. He taught his subjects proper custom, and his celebrated testament enjoined harmony upon his seven sons, whom he dispatched to found seven kingdoms, the eldest, Khun Lo, taking Luang Prabang. Lao dynasties down to the twentieth century traced their legitimacy to his line, and modern Lao historiography still debates his myth as the 'birth of the Lao race'.