Prior to the arrival of the Tai people and culture into what is now Thailand, the region had hosted a number of indigenous Mon-Khmer and Malay civilizations. Yet few are known about Thailand before the thirteenth century as the literary and concrete sources are scarce and most of the knowledge come from archeological evidences and assumptions.
Main article: Dvaravati
A 13 meter long reclining Buddha, Nakhon Ratchasima

The Chao Phraya valley in what is now Central Thailand had once been the home of Mon Dvaravati culture, which prevailed from the 7th century to the 10th century.[1] The existence of the civilizations had long been forgotten by the Thai when Samuel Beal discovered the polity among the Chinese writings on Southeast Asia as