 He was a younger son of Sancho III of Navarre and Muniadona of Castile, and by his father's will recognised the supremacy of his eldest brother, García Sánchez III of Navarre.While Ferdinand inaugurated the rule of the Navarrese Jiménez dynasty over western Spain, his rise to preeminence among the Christian rulers of the peninsula shifted the locus of power and culture westward after more than a century of Leonese decline.Nevertheless, "[t]he internal consolidation of the realm of León–Castilla under Fernando el Magno and [his queen] Sancha (1037–1065) is a history that remains to be researched and written."