Lạng Chượng is the great conquering ancestor of the Black Tai, the hero around whom the Táy Pú Xấc ('Following the Ancestors' Campaigns') is built. Setting out from the ancestral basin of Mường Lò, he leads a sweeping southwestward migration-conquest into Mường Muổi (Thuận Châu), Mường La, Mường Thanh and the surrounding valleys, defeating and displacing the earlier Xá (Khmuic) inhabitants and planting the lordly Tai settlements later organized as the Sip Song Chau Tai ('Twelve Tai Cantons'). Reckoned within the Lò lineage of Tạo Xuông and Tạo Ngần—though the intervening generations vary between recensions—he stands at the hinge of legend and remembered history, and is venerated as a powerful founding ancestral spirit. Sources differ on whether he is to be identified with the hero Chương of the great Tai epic.