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 founding of the Sukhothai Kingdom as the beginning of the Thai 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.