Si Inthrathit

Si Inthrathit (Thai: ศรีอินทราทิตย์, pronounced; also spelt Śrī Indrāditya) was the first king of the Sukhothai Kingdom, a historical polity in what is now Thailand. He reigned from 1238 until around 1270 and is credited as the founder of the Phra Ruang dynasty, regarded as the first historical Siamese dynasty.

Born Bang Klang Hao and ruler of Mueang Bang Yang, he took Sukhothai from Khom Sabat Khlon Lamphong in 1238 in alliance with his brother-in-law Pha Mueang of Mueang Rat. Pha Mueang declined the throne and invested him as ruler instead, passing on his own Khmer-conferred title of Si Indraditya. The episode has long been read as the liberation of Sukhothai from Khmer rule and the founding of an independent Tai kingdom; more recent work treats it as a contest between local lords who both held Khmer honours.