This was said in a low voice, but Beethoven heard it. The cloud disappeared from his brow. He raised his head, shook his mane, and with flashing eyes said to Mozart:

“No, sir, that is not a show-piece learned by heart that I played, but a free fantasie. In proof of this I ask you to give me a theme for another free fantasie, and then I will show you what I can do.”

Ludwig Van Beethoven (Life Stories for Young People) — Part 37

“Oho! Oho! don’t get too excited, young man,” replied Mozart. “You can have a theme—develop this one.”

Ludwig Van Beethoven (Life Stories for Young People) — Part 37

Mozart leaned over Beethoven’s shoulder, played the theme, and then stepped back a little. Beethoven instantly grasped the theme. He always played best when aroused, and at this instant he was still excited by the presence of the honored master. He developed the theme with such skill and brilliancy of technique that he carried his audience away with wonder at his inspired performance.

Ludwig Van Beethoven (Life Stories for Young People) — Part 37

All indifference and coolness disappeared from Mozart’s manner. With the young musician’s first passages and accords, deep interest was apparent on his countenance, and when Beethoven finished his fantasie and arose from the piano, Mozart went up to him, embraced him, and said in a tone of voice all could hear, “This young man, some day or other, will make a noise in the world.”

Now it was all joy and exultation. Beethoven was visibly affected, and trembled, while flashes of triumph shot from his piercing eyes. The princely couple and the guests overwhelmed him with congratulations.

After that evening Beethoven was regarded in Vienna as destined to musical greatness, and he found friends and well-wishers everywhere. Prince Lichnowski was completely devoted to him. He gave him a room in his palace, and a standing invitation to his table as a guest.

Beethoven thoroughly appreciated these friendly attentions, but he was not on that account any the less obstinate and self-willed. Proud of his genius, which the great Mozart had so clearly recognized, he did not display a fawning, servile manner. He seemed rather like one who was on guard against favors, than as one who was receiving them.

Prince Lichnowski, an extremely amiable man, and one who was well acquainted with the world, let Beethoven go his own way. He clearly recognized the great genius of his young friend, and did not trouble himself about the oddities, and at times rude ways, in his behavior. The Princess did the same. She valued and admired the inner worth of the young artist, and did not concern herself about his rough exterior.