Early Buddhist Thai state in northern Thailand founded in the 13th century, independent of the declining Khmer empire of Angkor. Its core towns were Sukhothai and Si Satchanalai. Under its greatest king Ram Khamhaeng (c 1275-1317), the power of Sukhothai expanded over vast areas of the Indochinese and even the Malay Peninsula. In the 15th century, the center of Thai power shifted south to Ayuthya and Sukhothai ceased to exist as an independent kingdom. It is also known for its glazed stoneware vessels, of the same name, widely exported. The pottery had underglaze decoration in black / brown on a cream slip.