Laotian kingdom that flourished from the 14th century until it was split into two separate kingdoms, Vien Chang and Luang Prabang, in the 18th century. Conflict with its Myanmar (Burmese) and Thai (Siamese) neighbours forced the kingdom's rulers to transfer the capital from Luang Prabang to Vientiane (1563), but the kingdom maintained its power and was at the height of its glory when the Dutch merchant Gerrit van Wusthof visited Vientiane in 1641.