The following December (1786), Mozart composed an aria (a "Scena con Rondo"), for Nancy and presented it to her as a gift (presumably for Christmas). The text was taken from his beloved opera Idomeneo and was really a vocal/piano duet, the piano part composed for him to play. It was his intentions that Nancy sing it at her Viennese farewell concert, which was scheduled for the night before the group's departure in February of 1787. In his thematic catalog, dated 27 December 1786, Mozart made the following personal entry next to the musical incipit of the aria: Für Mlle. Storace und mich (For Mademoiselle Storace and me). This is the only personal reference found in Mozart's thematic catalog.
The following is the scene from So Faithful a Heart where Mozart presents his gift to Nancy:
After supper, they all retired to the salon for a special presentation, for Mozart announced upon his arrival that he had a gift to give Nancy before he left for Prague. He motioned Nancy to step forward and join him at the fortepiano, where he sat, opening the aria. Knowing her excellent sight singing capabilities, he invited her to read through it with him in front of the other guests.
As she quickly leafed through the manuscript, she immediately recognized the text, and turned to him with tears brimming in her eyes. “I can’t believe you did this,” she whispered to him.
Mozart smiled sheepishly and replied softly, “It’s everything I wish to say to you, Wanze.” He silently mouthed the words to her in English, “I adore you, little bug.” He then played the opening measures of the recitative and she began to sing.
You advise me calmly to forget you and love another
and want that I still live?
Ah, No! I would rather die!
Come death! I wait for it courageously!
To seek consolation from another,
to give my love to another only fills my heart with dread!
Cruel suggestion! Ah! My despair will kill me.
Do not fear, my love will never be changed.
Faithful I shall always remain.
But my affliction has caused me to falter
and now my soul from grief must flee.
Are you sighing? O woe outpouring?
But all is vain to one who is begging.
O Heaven, I cannot express it!
Pity me, Heaven, see my anguish,
see the grief due to my affection!
Has ever such torment plagued so faithful a heart?
Has such doom or dejection ever beset such a loyal heart?
Hateful galaxies! Vile constellations!
Why should you beset me with such sorrow? Ah, why?
She thought that when he’d composed the role of Susanna, it was the ultimate in his public expression of his affection for her, but now this. Not even the tender, Deh vieni non tardar, which they had always considered their special aria, could compare. The music was passionate and tender all at once, and the piano part that he had composed for himself to play as a duet with her vocal line, wrapped itself around the vocal melody as a lover wrapping himself around the object of his devotion. She could hardly wait for her concert when they would perform it with the orchestra and she would be able to hear his piano line standing out from the orchestral accompaniment, mingling with hers in a public, musical declaration of what had taken place in their hearts and in their most intimate moments, behind closed doors.
After they finished the last bars, he stood and handed her the manuscript. She read the dedication aloud, “From your servant and friend…” and she threw her arms around his neck. He wrapped her in his embrace, the two of them remaining in one another’s arms for several moments as the small group of onlookers sat silently and watched, many of them moved to tears by what they had just heard and seen.