Liberation from Lawo[edit]
Wat Si Sawai, Sukhothai Historical Park
Prior to the 13th century, Tai kingdoms had existed on the northern highlands including the Ngoenyang (centered on Chiang Saen; predecessor of Lanna) kingdom and the Heokam (centered on Chiang Hung, modern Jinghong in China) kingdom of Tai Lue people. Sukhothai had been a trade center and part of Lawo, which was under the domination of the Khmer Empire. The migration of Tai people into the upper Chao Phraya valley was somewhat gradual.
Modern historians stated that the secession of Sukhothai (once known as Sukhodaya) from the Khmer empire began as early as 1180 during the reign of Pho Khun Sri Naw Namthom who was the ruler of Sukhothai and the peripheral city of Sri Satchanalai (now a part of Sukhothai Province as Amphoe). Sukhothai had enjoyed a substantial autonomy until it was re-conquered around 1180 by the Mons of Lawo under Khomsabad Khlonlampong.
Two brothers, Pho Khun Bangklanghao and Pho Khun Phameung took Sukhothai from Mon hands in 1239. Khun (ขุน) before becoming a Thai feudal, was a Tai title for a ruler of a fortified town and its surrounding villages, together called a muang; in older usage prefixed pho (พ่อ) father,[2] Comparable in sound and meaning to rural English Paw. Bangklanghao ruled Sukhothai as Sri Indraditya – and began the Phra Ruang Dynasty - he expanded his primordial kingdom to the bordering cities. At the end of his reign in 1257, the Sukhothai kingdom covered the entire upper valley of the Chao Phraya River (then known simply as Menam, "Mother of Waters," the generic Thai name for rivers.)
Traditional Thai historians considered the foundation of the Sukhothai kingdom as the beginning of their nation because little was known about the kingdoms prior to Sukhothai. Modern historical studies demonstrate that Thai history began before Sukhothai. Yet the foundation of Sukhothai is still a celebrated event.