Sancho III of Navarre
At the time of his death Fernando had no living sons. He was succeeded by his sister Teresa and her son, Ramiro III, as recorded during the reign of Sancho III of Navarre: "transitus est illo comite Ferdinando Anxurez; venit sua germana domina Tarassia et rex Ramiro, qui erat in Legione, venit a Monteson" ("this count Fernando Ansúrez died; his sister Lady Teresa came and king Ramiro, who was in León, came to Monzón"). This is notice is preserved in the abbey of Husillos, to which Teresa and her son granted the villages of San Julián and Abandella for the sake of Fernando's soul. Also on account of Fernando's childlessness, his widow, Toda, was allowed to rule Dueñas in the county of Monzón. In 980 she was referred to as "domna Tota cometissa iudicante ciui Domnas" ("the countess Doña Toda judging in the city of Dueñas").