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a medieval Thai principality. Its capital was the city of U Thong, the ruins of which are near ancient Suphanburi. In the first half of the 14th century, the prince of U Thong married the daughter of the ruler of the neighboring principality of Lavo; after his father-in-law’s death he united the two principalities, which became the nucleus of the future kingdom of Ayutthaya. In 1347, because of a cholera epidemic, the prince of U Thong moved from the capital city to one of the islands at the confluence of the Menam Chao Phraya and Pa Sak rivers, where he founded the new capital, Ayutthaya, and was crowned as Ramathibodi in 1350.