He was a younger son of Sancho III of Navarre and Mayor of Castile, and by his father's will recognised the supremacy of his eldest brother, García Sánchez III of Navarre.
He was a younger son of Sancho III of Pamplona and Muniadona of Castile, sister of García Sánchez of Castile. By his father's will recognised the supremacy of his eldest brother, García Sánchez III of Navarre.