The Thai have traditionally regarded the founding of the kingdom of Sukhothai as marking their emergence as a distinct nation. Tradition sets 1238 as the date when Tai chieftains overthrew the Khmer at Sukhothai, capital of Angkor's outlying northwestern province, and established a Tai kingdom. A flood of migration resulting from Kublai Khan's conquest of Nanchao furthered the consolidation of independent Tai states. Tai warriors, fleeing the Mongol invaders, reinforced Sukhothai against the Khmer, ensuring its supremacy in the central plain. In the north, other Tai war parties conquered the old Mon state of Haripunjaya and in 1296 founded the kingdom of Lan Na with its capital at Chiang Mai.