How it began
The script is attributed to Ramkhamhaeng, the third king of Sukhothai, in what is now north-central Thailand. He inherited a small kingdom about 1279 and ruled until 1298. The Museum Volunteers of Malaysia's national museum date the invention of the Thai alphabet to 1283. Britannica states that most of what is known of the king comes from his great inscription of 1292, the earliest extant inscription in the Thai language, written in a script devised by the king himself. Wikipedia classes this Sukhothai script as a Brahmic script.
How it spread
Ramkhamhaeng extended his influence as far as Vientiane and Luang Prabang in what is now Laos, west to the coast of Myanmar and south to Nakhon Si Thammarat. His vassals broke away after his death, but Sukhothai's successor states, especially Ayutthaya, built on its culture in the following centuries. Sukhothai itself was absorbed into Ayutthaya in 1438.
What changed first
The inscription used the new script to describe the kingdom. It portrays Ramkhamhaeng as a patriarchal ruler whose justice was available to all, a patron of Buddhism, a promoter of trade and a friend to neighboring rulers. UNESCO notes that its detailed description of the 13th-century Thai state of Sukhothai is rare. Under Ramkhamhaeng, Britannica says, Sukhothai became the cradle of Siamese civilization, and the arts developed distinctively Thai forms.
What lasted
Apart from local legends, Ramkhamhaeng was all but forgotten until 1834, when Mongkut, the future king of Siam who was then a Buddhist monk, rediscovered the inscription of 1292. Ramkhamhaeng has since been regarded as a national hero in Thailand. The inscription was used as evidence in Thailand's successful proposal to list the Historic Town of Sukhothai and Associated Historic Towns as World Heritage in 1991.
Where it stands today
UNESCO has entered the King Ram Khamhaeng Inscription in its Memory of the World register. Its description says the stone records the invention of the Thai language scripts that are the foundation of the modern scripts used in Thailand by 60 million people.
