ALREADY WE HAVE encountered the mekong River valley several times in connection with the early history of Siam, and we shall soon meer it again. But in treating the early history of Siam, it is customary to find scant references to the Mekong valley before the Bangkok period. What is the point now of mentioning it earlier ? Though there are exceptions it is usual to include the north- eastern part of Siam in the history of Laos until the French took over Laos in 1893, and only to include it in Siam/Thailand af ter that date. However, if we carefully consider the treatment of the Khorat Plateau in this way, we might ask ourselves, Do we really want so to privilege political history? Suddenly, over- night, at the stroke of a pen, does the northeastern part of what is now Thailand cease being "part" of Laos and become there- after a "part" of Thailand? we might instead let a part of the world "declare" its membership in one part of history or another by how it behaves. In such terms, the middle Mekong valley in the early centuries AD is a part of the history of Dvaravati; that is, that