 He became king in 1479 after the abdication of his father Chakkaphat Phaen Phaeo, who had fled the capital of Muang Sua ahead of the Đại Việt armies.Prior to his accession he served as Governor of Muang Dansai, according to the Lao chronicles he commanded Lao forces at the Battle of Pakphun where the invading forces were halted and forced to retreat to Vietnam.Souvanna Banlang was born in 1455 as Prince Then Kham the second son of King Chakkaphat Phen Phaeo.