Luang Prabang had been the first capital of Lan Xang since the early establishment of the kingdom. Its earlier name was Mueang Sua which was awarded to Khun Lo by his father Khun Borom. Khun Lo established a dynasty and renamed the city Mueang Xieng Thong.
Time passed to the Fa Ngum's era (born 1316-died 1393). Fa Ngum and his father, Chao Fa Ngiao, were banished to the Khmer kingdom of Angkor by his own grandfather Souvanna Khampong. Having been married to a Khmer princess and with the support of the king of Angkor, Fa Ngum returned with an army to gain control of his kingdom. During his reign in 1353-1374, Fa Ngum found his kingdom in the name of Lan Xang which means "land of millions elephants and a white parasol. " He brought the Prabang Buddha image from Angkor to be enshrined in Viang Chan Vieng Kam (now Vientiane). The Prabang has become the Laotian's spiritual protector since.
Fa Ngum named Xieng Thong the capital city as Cri Satna Khanahut Uttamra and in fulfilling his wife's wish made Theravada Buddhism the state religion by legitimatizing this quest with the Prabang Buddha image. The name Luang Prabang was derived from this Prabang Buddha image which used to be enshrined in Xieng Thong.