Following the decline of the Khmer empires, the area was settled by groups of Lao in the late 18th century and they founded the capital city. By the early Ratanakosin era it had become part of monthon Ubon, a southeastern Isan satellite state extending across what are now Surin, Si Saket and Ubon Provinces – as well as parts of southern Laos – with Champasak, Laos, as monthon capital.