In 1215 his father married him to Peronella, daughter of Bernard IV of Bigorre, but the marriage was annulled by Pope Honorius III the very next year (1216). James reached his majority in 1223, the year Sancho died, and Nuño began serving James as chief advisor in matters relating to the Viscounty of Béarn.
In 1215, his father married him to Peronella, daughter of Bernard IV of Bigorre; this marriage was annulled by Pope Honorius III shortly after (1216). By 1223, James reached adulthood and Sancho died in the same year. Nuño began serving as James's chief advisor concerning the Viscounty of Béarn.