He was the son of Peter II and a Matelle de Baux. When his father died in 1153, he inherited his title under the regency of his grandmother Guiscarda. When Guiscarda died in 1154, the Bearnese assembly put him under the tutelage of Raymond Berengar IV of Barcelona and did homage to the Catalan at Canfranc.
As the son of Peter II and a Matelle de Baux, he succeeded his father upon his death in 1153. Under the regency of his grandmother Guiscarda, he inherited the title. When Guiscarda died in 1154, the Bearnese council appointed him as a ward to Raymond Berengar IV of Barcelona, and he pledged allegiance to the Catalan at Canfranc.