Carl Czerny's autobiography from 1842 lies In the archives of Gesellschaft der Musikfreunde in Vienna. Here Czerny tells the story of his relationship to Beethoven and of their first meeting in 1801: ( ) are Czerny's and  [ ] are mine.

At this time we were often visited by an old man: [Wenzel or Vaclav] Krumpholz (a brother to the inventor of the pedal Harp) - indeed he almost came every day [old? - well he was fifty]. He was a violinist and member of the orchestra at the Court Theater and a music lover of almost extravagant passion. Although his technical knowledge was rather limited - mother nature had endowed him with such a precise instinct for musical beauty that with his judgment of any piece he was able to predict the verdict of the musical world.

When the young Beethoven appeared in Vienna with the determination to "conquer" the city Krumpholz at once attached himself to him with such a vigour that he soon became a trusted companion. He often spent the whole day with Beethoven who - though otherwise very reticent about any new composition he was working on - entrusted him all his new ideas. He very often played them to Krumpholz and would every day improvise on the piano for him.

It is true that Beethoven often poked fun at Krumpholz by calling him his "court jester", but it was obvious that the composer was very attached to the old man and perhaps this relationship gave him some important support against his enemies who were very numerous at this time when the broad public hardly understood his music - preferring the school of Mozart and Haydn.

This was the man for whom I had to play Beethoven's works - day in and day out - but even though he knew very little about piano playing he could of course advise me about tempi, interpretation, effects and character since he had often been together with Beethoven when the works were composed. His enthusiasm was so catching that I became a Beethoven devotee myself and in spite of my age soon learned all his works by heart. Krumpholz also told me of the works that were coming "out of Beethoven's pen" at that very moment and either sang or played [on his violin] the themes he had heard that same morning. In this way I was the first to know the works - but later I was also able to see how long Beethoven would work on a composition before he would publish it and how he in a new work would use themes that he had been inspired by years before. My close friendship with Krumpholz lasted until his death in 1817.

Graben (The Ditch) in Vienna - viewed (north-west) towards Kohlmarkt (The Coal 
Market). Further on in the background and a little to the right lies Tiefer Graben
(The Deep Ditch) where Beethoven had an apartment (nr. 10, Greinischer Haus) 
from January 1800 to spring 1801. Mozart also once had an apartment there
 (nr. 18). Today the street ends in Concordia Platz towards north-east. 

I was about ten years old when he took me to see Beethoven - it was a day that I both dreaded and looked forward to - the day when should finally meet the admired master. Even today it stands before me in the most vivid manner. It was winter [probably February 1801] when my father, Krumpholz and I left Leopoldstadt where we lived and drove to the inner part of Vienne to the street called Tiefer Graben and ascended an endless amount of stairs to the fifth or sixth floor [in fact Beethoven only lived on the fourth floor - but to young Carl it must have been an endless journey] where a rather disorderly servant opened the door and announced us to Beethoven. The room was a total mess; papers, pieces of clothes were lying all over, some trunks, bare walls and there was hardly a chair except for the rickety one at the Walter piano (this piano being the best in Vienna at that time). 

Viennese Walter piano from 
about Beethoven's time - in 
   fact this one was Mozart's    

In the room about 6 or 8 persons were assembled - among them the two Wranitzky brothers, [Franz Xaver] Süssmayr [who completed Mozart's Requiem], Schuppanzigh and one of Beethoven's brothers. Beethoven himself was wearing a dressing gown made of some longhaired darkish gray material and trousers that matched. He reminded me of Robinson Crusoe of whom I was reading at that time - his hair was coal black - cut like emperor Titus' - and it stood unkempt out in all directions from his head. He had not shaved for several days which made his already brown face look even darker. With my childish quick perception I at once noticed that in his ears were cotton wool that had been soaked in some yellow fluid. But at this moment there were no obvious signs of his coming deafness.

I was as once urged to sit down at the piano and play but I dared not start with one of his compositions so I played Mozart's great C major concerto (nr. 25  KV. 503). Beethoven at once gave me his whole attention and in the places where I only played accompanying passages he joined in and played the orchestral melody with his left hand. His hands were very hairy and the fingers very thick at the ends.

His satisfaction with my playing encouraged me to go on with his "Pathétique" sonata which had just been published [actually it was published in 1799 - but that was "new" in those days] and I finished with [the song] Adelaïde to which my father sang with his quite pleasant tenor voice. When we had finished Beethoven turned around to my father and said: "The boy has talent - I'll teach him myself - and accept him as my pupil. Send him to me several times a week but first you must get a copy of [Carl Philipp] Emanuel Bach's book about The True Art of Piano Playing, because he is going to bring that the next time he comes here".

Everybody in the room congratulated my father with the result and especially Krumpholz was very pleased. And - my father hurried out to buy the required book.

Beethoven in 1801

There are a lot of interesting things to be learned from this story. First of all Czerny's remark about the cotton wool in Beethoven's ears. This is probably one of the first observations we have about the problems with his ears. Later - in a letter to Otto Jahn - Czerny tells that Beethoven had been tormented by pains in his ears since 1800 but up till 1812 he was able to hear speech and music almost perfectly - and even after that he was able to hear to some degree partially with the help of different devices constructed by Court Mekanicus, Johann Nepomuk Mälzel (inventor of the metronome) before he became completely deaf. On the other hand Beethoven must have been frightened by the obvious consequences already at that time since he wrote the Heiligenstadt Testament one and a half year later in October 1802 in which he informs his brothers about his progressing deafness. 

  Mälzel's hearing aids constructed for Beethoven

It is also interesting to know that Beethoven must have known Mozart's concerto since he was able to play the orchestral part by heart accompanying Czerny. Of course a trained musician will always be able to fake an accompaniment of any piece by a minor composer just by hearing the themes from the solo passages - especially a composer whose music is very predictable - but not a Mozart. In those pre-CD-days there were only two possibilities to get to know a work - either go to a concert where it was played or study the score yourself. The chances of hearing such a concert more than a very few times was were very small, so we must assume that Beethoven had studied the score.

Beethoven was not very willing to take pupils but he did make exceptions to this in case of special talents and the remark about several times a week must have been a proof of this very special talent of Czerny's. And according to him Beethoven - the teacher - was quite different from Beethoven - the man. In this capacity - and with a talented pupil he was very patient and kind - not showing the violent temper that otherwise was customary - even resulting in fights at restaurants where he would throw the whole meal in the face of the waiter if he didn't like it.

The lessons focused in the beginning on scales and technique and then moved on to Beethoven's major emphasis on legato technique. This could be seen as some sort of starting all over for a boy, who could play both a Mozart concerto and the Pathétique sonata, but it could also be seen as a sign of Beethoven's emphasis on details. He must have seen Czerny as a diamond in the rough and wanted to make the perfect gem out of him - according to his own ideals. The lessons stopped around 1803 when Beethoven needed more time to concentrate on composition but the two remained on very close terms indeed - with Czerny being asked to proof read all his newly published works and the composer entrusting his pupil to make the piano reduction of the opera Fidelio in 1805. And when Beethoven had taken over the responsibilities of his nephew Karl - it was Carl Czerny who in 1816 was chosen as his piano teacher.

Karl van Beethoven - the composer's 
rather complicated nephew    

(Some few more words about Krumpholz: he was also a mandolin player (Thayer describes him as a mandolin virtuoso) and it was probably for him Beethoven wrote two sonatinas for mandolin and piano in C minor WoO 43 (1795) and C major WoO 44 (1796).
Beethoven's true attachment to Krumpholz can be seen by how deeply he felt his death on 2nd May 1817. The following day Beethoven composed Gesang der Mönche (Song of the Monks from Schiller's Wilhelm Tell) for two tenors and bass without accompaniment: Rasch tritt der Tod "in commemoration of the sudden and unexpected death of our Krumpholz". The piece only lasts ca. one minute and was never meant to be performed. It was some sort of musical memo to himself - and a somber, serious and a deeply felt one at that.)