In order to prove whether Aïda's love was still the same, Amneris, in the course of conversation, announced that Radames had been killed in battle, and her frown grew deeper still when Aïda, full of grief at this terrible news, broke forth into a tearful lament. As a further proof, however, she added immediately: "Nay, I did but wish to fright thee! Calm thyself, for the brave Radames lives yet!"
Upon hearing this, Aïda, her face transfigured with joy, sank upon her knees, and uttered a prayer of gratitude that her beloved one had been saved; and then, Amneris, unable to restrain her jealous anger any longer, sprang forward with blazing eyes, crying with haughty fury: "What, thou, a slave, to dare to aspire to one whom the daughter of Pharaoh deigns to love! Know, rash maiden, that the Princess of Egypt will brook no rival!"
Then, unheeding Aïda's gentle plea for mercy, the passionate Princess bade her prepare to meet her doom, since she was determined to humble her to the dust for her presumption; but at that moment, hearing sounds which told her that the festival was about to commence, her mood suddenly changed to expectancy again, and she went to join her father upon the throne which had been set up at the city gates, through which the triumphal procession had to pass, bidding Aïda attend her.
Radames was received with great kindness and favour by Pharaoh, who showered praises and thanks upon him for the mighty deeds he had performed; and as the young conqueror knelt, overcome, at the foot of the throne, the Princess Amneris with her own hands placed the crown of victory upon his brow with gentle tenderness.
The King now desired to see the prisoners who had been taken in battle; and as the captives one by one passed the throne, Aïda uttered a cry of surprise and grief, and, running into the arms of Amonasro, who was one of them, greeted him tenderly as her father. Amonasro, however, whispered to her not to disclose his true identity; and so when the company gathered round, on hearing that he was the beautiful slave-girl's father, the disguised king related a feasible story as to his capture, describing himself as an ordinary Ethiopian officer, which was readily enough believed.
Pharaoh now desired Radames to name any favour he pleased, which should be immediately granted; and the young victor, whose heart was as yet unhardened by the fortunes of war, besought the King to set all the captives free, as his reward.
But Ramphis, the High Priest, and the other counsellors declared that this would be an act of folly; and when they saw that Pharaoh would not deny the request that had been made, they entreated that at least it would be better to retain Aïda's father as a hostage of peace. To this, Pharaoh agreed, giving orders that all the other captives should be set free; and then, leading Amneris forward, he placed her hand in that of Radames, declaring before all the people that the Princess of Egypt was the prize he had destined for the deliverer of the country.
Amneris was radiant with joy, having thus secured her dearest wish, and feeling that she need no longer fear Aïda as a rival; but Radames was plunged in despair, for he was determined to wed no other maid but Aïda, whom he loved so passionately, and for whose sweet sake he had crowned himself with laurels. Aïda, too, was filled with grief, for Radames wed, naught remained to her but death.
Radames, however, saw that nothing was to be gained just then by refusing to accept the reward offered to him; and so he prudently permitted himself to be regarded as the affianced husband of Amneris, trusting to find some means of disentangling himself later on. He still saw Aïda from time to time in the palace, and sometimes found means to address a few words to her; but these opportunities were few and far between; and at last, despairing of ever securing a sufficiently long interview in which to talk over their plans, he invited her to meet him on the eve before his wedding-day, outside the Temple of Isis.
Now, Amonasro, who was also lodged in the Palace, had quickly observed the love that existed between Aïda and Radames; and having learnt from the soldiers that the scattered forces of Ethiopia had once more been banded together to invade Egypt, he determined to make use of his daughter's love as a means of securing information as to the Egyptians' war plans. For this reason, having overheard the arrangement made for the lovers' meeting, he managed to creep unseen by the guards from the palace, and made his way to the Temple of Isis.