Henry IV, in his second year as king, travelled to Úbeda and stayed with Beltrán's father, Diego Fernández de la Cueva, 1st Viscount of Huelma.

Most of the extant contemporary sources about Henry's potency are suspect, as the royal chronicles of his reign were either written or revised under the influence of Isabella, whose personal interest in the succession caused her to take great pains to insist on Joanna's illegitimacy.

Much of Isabella's attention to Henry, in fact, was spent on harming his reputation in order to cement the legitimacy of her own reign.

Royal chronicler Alfonso de Palencia, known for his particularly venomous attitude toward Henry, made many allusions in his writings that can be interpreted as accusations concerning Beltran's sexuality.

In 1467, he fought in the Second Battle of Olmedo against the faction who had claimed to depose Henry in favor of his brother Prince Alfonso.

Henry died in December, and this latest title was confirmed by the new Queen Isabella I of Castile and her consort Ferdinand II of Aragon on 20 April 1475.