Fa Ngum
The Phra Bang arrived in Lan Xang during the reign of Fa Ngum from Angkor, and was used to spread Theravada Buddhism in the new kingdom. In 1359 the Khmer king gave the Phra Bang to his son-in-law, the first Lang Xang monarch Fa Ngum (1353-1373); to provide Buddhist legitimacy both to Fa Ngum's rule and by extension to the sovereignty of Laos. The former Lao capital Luang Prabang, where it was kept, is named after the Buddha image.