The Siamese state based at Ayutthaya in the valley of the Chao Phraya River grew from the earlier kingdom of Lopburi, which it absorbed, and its rise continued the steady shift southwards of the centre of gravity of the Tai-speaking peoples. U Thong was an adventurer allegedly descended from a rich Chinese merchant family who married royalty. In 1350, to escape the threat of an epidemic, he moved his court south into the rich floodplain of the Chao Phraya. On an island in the river he founded a new capital, which he called Ayutthaya, after Ayodhya in northern India, the city of the hero Rama in the Hindu epic Ramayana. U Thong assumed the royal name of Ramathibodi (1350-69).