SRI INDRADITYA.

Pho Khun Sri Indraditya (Thai: พ่อขุนศรีอินทราทิตย์) (also Sri Intraditya, Si Inthratit) is said, according to the Number One Stone Inscription, to be the founder of the so-called Phra Ruang Clan, or 'dynasty' of the Sukhothai Kingdom. He ruled between the years of 1238 and circa 1270 C.E.
Initially, he served as the 'vassal' lord of Bang Yang, a territory which belonged to the westernmost regions of the Khmer Angkor kingdom in that time, and now lies in the northern-central region of Thailand. He assumed the name Khun Bang Klang Thao, or simply Hao, during his time in this office. Together with the Governor of Rad, Khun Pha Mueang, he declared independence from Angkor's control and its prohibitive taxes, a crucial motivating factor in the revolt. Extensive Khmer preoccupation with great architectural works weakened the ability and readiness of Khmer defenses, greatly aiding the rebellion indirectly.
Initially Khun Bang Klang Thao, or Khun Bang Klang Hao, Lord Who Rules Sky, was then declared the king of the new kingdom, taking a name of Sanskrit origin, Sri Intraditya, The Sun King with the Power of Indra, His skill and bravery greatly impressed the people of the kingdom, who thus conferred the title Phra Ruang (Glorious Prince). This surname was given to all kings of Sukhothai to follow, giving rise to the first Thai dynasty, the Phra Ruang.
Sri Intraditya and his queen, Queen Nang Suang, had three sons. The eldest died at a young age, the second was named Ban Mueang, and the third son defeated a Khmer prince in an encounter of mounted combat on elephants; he named this youngest son Ramkhamhaeng (Rama the Bold) in tribute to the feat. Sri Intraditya died around 1270 C.E., and was succeeded by his son, Ban Mueang.