It is at this juncture, as Gaspar departs, that Ferdinand appears at court, returning from the war, in which he has not only distinguished himself by his valour, but actually has saved the kingdom. Alfonso asks him to name the prize which he desires as recompense for his services. Leonora enters. Ferdinand, seeing her, at once asks for the bestowal of her hand upon him in marriage. The King, who loves her deeply, and has nearly risked the wrath of the Pope for her sake, nevertheless, because immediately aware of the passion between the two, gives his assent, but with reluctance, as indeed appears from the irony that pervades his solo, "A tanto amor" (Thou flow'r belov'd).
He then retires with Ferdinand.
Leonora, touched by the King's magnanimity, inspired by her love for Ferdinand, yet shaken by doubts and fears, because aware that he knows nothing of her past, now expresses these conflicting feelings in her principal air, "O, mio Fernando," one of the great Italian airs for mezzo-soprano.
[[Listen]]
O, mio Fernando, della terra il trono
She considers that their future happiness depends upon Ferdinand's being truthfully informed of what her relations have been with the King, thus giving him full opportunity to decide whether, with this knowledge of her guilt, he will marry her, or not. Accordingly she despatches Inez with a letter to him. Inez, as she is on her way to deliver this letter, is intercepted by Gaspar, who carries out the King's command and orders her arrest. She is therefore unable to place in Ferdinand's hands the letter of Leonora.
Into the presence of the assembled nobles the King now brings Ferdinand, decorates him with a rich chain, and announces that he has created him Count of Zamora. The jealous lords whisper among themselves about the scandal of Ferdinand's coming marriage with the mistress of the King; but Leonora, who enters in bridal attire, finds Ferdinand eagerly awaiting her, and ready to wed her, notwithstanding, as she believes, his receipt of her communication and complete knowledge of her past.
While the ceremony is being performed in another apartment, the nobles discuss further the disgrace to Ferdinand in this marriage. That Leonora was the mistress of the King is, of course, a familiar fact at court, and the nobles regard Ferdinand's elevation to the rank of nobility as a reward, not only for his defeat of the Moors, but also for accommodatingly taking Leonora off the hands of the King, when the latter is threatened with the malediction of Rome. They cannot imagine that the young officer is ignorant of the relations that existed between his bride and the King.