The first act was rehearsed at the end of November, and Mozart was able to report to his father such success as raised the general expectation to a still higher pitch (December 1, 1780):—
The rehearsal went off remarkably well. There were only six violins in all, but the proper wind instruments. No spectators were admitted but Seeau s sister and young Count Seinsheim. I cannot tell you how delighted and astonished every one was. It was only what I expected, for I assure you I went to this rehearsal with as light a heart as if it had been a banquet. Count Seinsheim said to me: "I assure you I expected much from you, but this I did not expect." The Cannabich family and all who know them are true friends of mine. I went home with Cannabich after the rehearsal. Madame Cannabich met us and embraced me, full of pleasure that the rehearsal had gone off so well; then came Ramm and Lang half out of their minds with delight. The good lady, my true friend, being alone in the house with her sick Rose, had been full of anxiety for me. Ramm said to me (if you knew him you would call him a true German, for he says to your face exactly what he thinks): "You may believe me when I say that no music ever made such an impression on me; and I thought fifty times what a pleasure it will be to your father to hear this opera." But enough of this! My cold was made rather worse by the rehearsal. One cannot help getting overheated when fame and honour are at stake, however cold-blooded one may naturally be.
Wolfgang's father received other confirmation of the success, which he did not withhold from his son:—
Fiala showed me a letter from Becke which is very eulogistic of the music of your first act. He writes that tears of joy and pleasure came to his eyes when he heard the music, and that every one declared it was the finest music they had ever heard—all so new and beautiful, &c. He says that the second act is about to be rehearsed, that he will write to me himself, &c. Well, God be thanked, this all looks well.
L. Mozart, who had been wont to exhort Wolfgang not to procrastinate, as indeed he often did at Salzburg, was now concerned to hear of his obstinate cold, the more so as his sister was suffering from a chest complaint, and he begs him to take care of himself; he was not to hurry over the third act, it would be ready quite in good time. Ready, as he always was, with good advice, he warns him to remember that an opera should not only please connoisseurs (December 11, 1780): "I recommend you not to think in your work only of the musical public, but also of the unmusical. You know that there are a hundred ignorant people for every ten true connoisseurs, so do not forget what is called popular, and tickle the long ears." But Wolfgang will not listen to this. "As to what is called popular," he answers (December 16, 1780), "do not be afraid, there is music in my opera for all sorts of people—only none for long-ears." Meantime the work of rehearsing went steadily forward. On December 16, in the afternoon, the first and second acts were rehearsed at Count Seeau's, the parts being doubled, so that there were twelve violins. All went well, as Wolfgang reported (December 19, 1780):—
The orchestra and all the audience gladly acknowledged that, contrary to their expectations, the second act was superior both in novelty and expression to the first. Next Saturday the second act is to be rehearsed again, but in a large room in the palace, which I have long desired, for the room at Count Seeau's is far too small. The Elector is to listen incognito in an adjoining apartment. "We must rehearse for dear life then," said Cannabich to me. At the last rehearsal he was bathed in perspiration. You will judge from my letters that I am well and hearty. It is a great thing to come to the end of a great and laborious work, and to feel that one leaves it with honour and fame; this I have almost done, for now nothing is wanting but three songs, and the last chorus of the third act, the overture and the ballet—"et adieu partie!"
The next rehearsal gave even greater satisfaction (December 27, 1780):—
The last rehearsal was splendid; it was in a large room in the palace, and the Elector was present. This time we had the whole orchestra (that belongs to the opera-house, of course). After the first act the Elector said "Bravo!" out loud; and when I went to pay my respects to him, he said, "This opera will be charming—it will certainly do you honour." As he was not sure of being able to remain to the end, we let him hear the concerted song, and the storm at the beginning of the second act. These he also approved of in the most kindly manner, and said, laughing, "No one would imagine that such great things could come out of such a little head." The other day at his early reception, too, he praised my opera very much.