Uthong

King U-thong (; ) or King Ramathibodi I (; ; , 1314–1369) was the first King of Ayutthaya, reigning from 1351 to 1369.

Ramathibodi I was the son of a mixed Mon–Chinese monarch Baramaraja, previously a prince of Si Satchanalai who subsequently ascended the throne of Xiān's Ayodhya, and Sunandhadevī, a younger princess of the court of Suvarnaraja, the ninth monarch of Xiān. Originally known by the title Varashreṣṭhakumāra (วรเชษฐกุมาร), he succeeded his father as king of Xiān in 1344. In 1351, he was formally enthroned as the founding monarch of the Ayutthaya Kingdom. His maternal lineage can be traced back to the Dvaravati period, specifically under the ruling dynasty of the polity situated in the Phraek Si Racha region, which is referred to in Chinese sources as Xiū Luó Fēn.