While the origin of the Plain of Jars people is unknown, the recorded history of Xiangkhouang is interlinked with the Tai Phuan. The Tai Phuan or Phuan people are a Buddhist Tai-Lao ethnic group that migrated to Laos from southern China and by the 13th century had formed the independent principality Muang Phuan at the Plain of Jars with Xiangkhouang (the contemporary Muang Khoun) as the capital. They prospered from the overland trade in metals and forest products. In the mid-14th century, Muang Phuan was incorporated into the Lane Xang Kingdom under King Fa Ngum.