Ramkhamhaeng (born 1239?—died 1298) was the third king of Sukhothai in what is now north-central Thailand, who made his young and struggling kingdom into the first major Tai state in 13th-century Southeast Asia.
On the death of his brother, King Ban Muang, about 1279, Ramkhamhaeng inherited his tiny kingdom of only a few hundred square miles. Over the next two decades—by careful diplomacy, shrewd alliances, and military campaigns—he extended his power and influence as far as Vientiane and Luang Prabang in what is now Laos, west to the Indian Ocean coast of Myanmar (Burma), and south on the Malay Peninsula to Nakhon Si Thammarat. It is likely that he did not directly rule all this area but rather gained the recognition by local rulers of his suzerainty. He united a region that shared a new faith in Therāvada Buddhism and a hostility toward the Cambodian kingdom of Angkor, which earlier had dominated the region. Missing from the Sukhothai empire was the eastern half of the lower Chao Phraya River valley, which in the 14th century was absorbed by Ramkhamhaeng’s successors and became the core of the new Tai kingdom of Ayutthaya (Siam).
Most that is known of Ramkhamhaeng comes from his great inscription of 1292, the earliest extant inscription in the Thai language, in a script devised by the king himself. It portrays him as a patriarchal ruler whose justice and liberality were available to all. He was an ardent and generous patron of Buddhism, a promoter of trade, and a friend to neighbouring rulers. Under Ramkhamhaeng, Sukhothai became the cradle of Siamese civilization. The arts developed distinctively Thai expressions, and Sukhothai bronze sculpture reached an especially high level. Ceramics, based on techniques borrowed from China, were produced at Sukhothai and Sawankhalok and became a major item of international trade.
Ramkhamhaeng’s kingdom was built upon the personal power and magnetism of an exceptional ruler, and when the king died, his distant vassals soon broke away. The region, however, was left with a vision of unity and a sense of cultural integrity upon which Sukhothai’s successor states, especially Ayutthaya, were to build in following centuries.
Save for colourful local legends, Ramkhamhaeng was all but forgotten until 1834, when King Mongkut of Siam, then a Buddhist monk, rediscovered his 1292 inscription. Ramkhamhaeng since came to be regarded as a national hero in Thailand.