I was about eleven years old when my respected teacher Czerny took me to see Beethoven. Already a long time before, he had told Beethoven about me and asked him to give me a hearing some day. However, Beethoven had such an aversion to infant prodigies that he persistently refused to see me. At last Czerny, indefatigable, persuaded him, so that, impatiently, he said, “Well, bring the rascal to me, in God’s name!” It was about ten o’clock in the morning when we entered the two small rooms in the Schwarzpanierhaus, where Beethoven was living at the time, (1) myself very shy, Czerny kind and encouraging. Beethoven was sitting at a long, narrow table near the window, working. For a time he scrutinized us grimly, exchanged a few hurried words with Czerny and remained silent when my good teacher called me to the piano. The first thing I played was a short piece by Ries. When I had finished, Beethoven asked me whether I could play a fugue by Bach. I chose the Fugue in C minor from the Well-Tempered Clavichord. “Could you also transpose the fugue at once into another key?” Beethoven asked me. Fortunately, I could. After the final chord, I looked up. The Master’s darkly glowing gaze was fixed upon me penetratingly. Yet suddenly a benevolent smile broke up his gloomy features, Beethoven came quite close, bent over me, laid his hand on my head and repeatedly stroked my hair. “Devil of a fellow!” he whispered, “such a young rascal!” I suddenly plucked up my courage. “May I play something of yours now?” I asked cheekily. Beethoven nodded with a smile. I played the first movement of the C major Concerto. When I had ended, Beethoven seized both my hands, kissed me on the forehead and said gently, “Off with you! You’re a happy little fellow, for you’ll give happiness and joy to many other people. There is nothing better or greater than that!” This event in my life has remained my greatest pride, the palladium for my whole artistic career. I speak of it only very rarely and to my intimate friends.
Source: Michael Hamburger, cited in: Marek, George (1969) Beethoven: Biography of Genius. London: William Kimber, p. 575-576.
(1) Beethoven, was in fact not living there at the time.