The history of Isaan is complex and multi-layered and varies considerably depending on which part of the region you are travelling through. Southern Isaan, the part along the border with Cambodia, was under the control of the Angkorean Empire from an early period of history and boasts a wealth of Khmer temples from between the seventh and thirteenth centuries. Central Isaan contains a larger number of Mon moated settlements, some of which contain carved boundary stones, but it eventually came under the vassalage of Angkor as well. In contrast, Northern Isaan has a comparative paucity of Khmer monuments. Its main foreign influence was always Laos and the Isaan dialect spoken there is much closer to the language of Vientiane than classical Thai. These linguistic links are a reflection of earlier political control, first from the Laos-based kingdom of Lan Xiang (The Land of a Thousand Elephants) and the later Kingdom of Vientiane.
These Lao kingdoms have left an architectural legacy in the form of the beautiful Lao-style chedis which are found in Northern Isaan and along both sides of the Mekong River. One of the most striking of these chedis can be found at Wat Phra That Choeng Chum in the modern city of Sakhon Nakhon. This slender Lao-style chedi is said to represent an angled lotus bud. Measuring twenty-four metres in height, the lower portions are a brilliant white and the upper parts are gold. Its elegant proportions make it a singularly lovely chedi in a country full of such structures. It has become a symbol of the province of Sakhon Nakhon, being featured on its official seal. It is also featured on the tails side of the ten satang coin. The current design of this elegant structure dates to the eighteenth century, making it a likely product of the kingdom of Vientiane, but this is only the latest incarnation of the chedi. Its earliest history extends back as far as the tenth century with the arrival of the Khmers in the area.
It is thought that Phra That Choeng Chum was built over a 10th century Khmer prang (tower). The original structure was built to cover footprints of four Buddhas, namely Phra Kakusantha, Phra Konakom, Phra Kassapa, and Phra Kodom. Nor are the vestiges of the original prang the only Khmer relic within the city of Sakhon Nakhon; a number of stupas are also scattered around town. Therefore, we can assume that Sakhon Nakhon was once a major Khmer city. The wealth of temple remains indicates that it was also a religious centre of some kind. A trace of this religious heritage can still be felt in the city today: the modern temple of Wat That Choeng Chum remains a site of veneration for Thai pilgrims.
In the vihaan of the wat, there is a further hint of the great antiquity of the site. Here you can find perhaps the most celebrated Buddha image of the entire province, Luang Por Oen Saen. Said to date back to the middle of the thirteenth century, it is cast in the Chiang Saen style, indicating the earliest arrival of Thai or Lao culture in the area. Behind the statue is another small room with a number of small Buddhas and other religious relics on display. Clearly, the site was of symbolic significance to a number of kingdoms over many centuries. The Khmers, the Lao and the Thais have all come to worship at this important place.