The early thirteenth century saw the beginning of the last and greatest influx of Lao into the south of Siam. The suppression of the Lao-Tai undertaken in southwestern China, culminating in the decisive victories of the Emperor Kublai Khan, drove many thousands of these people down into the mountainous regions of northern Siam, where the newcomers upset the balance of power among their predecessors and caused the disruption of several of their states. As a result, many impoverished petty chieftains of ancient lineage gathered their people together and set off down the rivers to seek new fortunes in the kingdoms to the south. During the following century, mingling with the Khmer and the Lao-Khmer and acquiring great strength of numbers, the Lao wrested control from the original inhabitants and established capitals of their own, one of which, Supanburi, was in time to become dominant over all the rest. When, at the middle of the fourteenth century, Phra Chao Uthong, King of Supanburi, fleeing from a pestilence, marched westward to found a new capital, Nong Sano, now the seat of the weak successors of the great Suthammarat, fell into his hands almost without a struggle, its King fled to Cambodia, and Uthong erected near the fallen city the new city of Maha Nakhon Si Ayuthaya (Ayuthia), which was destined to become famous throughout the world as the capital of one of the greatest kingdoms in the history of Farther India. KINGDOM OF AYUTHIA Phra Chao Uthong (under the name of Phra Ramathibodi) became King at Ayuthia in A.D. 1350 and thereafter was fully occupied in bringing the outlying states and provinces into line, in organizing his government, and in setting up a system of law, parts of which continue in use to the present time. Before his death in 1369, he had brought together the whole of the components of the Sukhothai-Sawankhalok Kingdom and had welded them so closely together that, when Cambodia, annoyed by the independent attitude of what was theoretically its vassal, sent an army to reassert its rights of suzerainty, the united Siamese not only defeated the enemy but pursued him well within the confines of his own country. Under Ramathibodi's successors the Kingdom continued to prosper. During the next two centuries, Buddhism definitely succeeded Brahmanism as the popular religion throughout the country and great treasure was expended in beautifying the cities by the erection of graceful temples and reliquaries in the adapted Cambodian style which persists in Siam to this day.