Kevin Sutton, in response to Jereme McMillan, wrote:

>>Before that the pianist, who was usually the composer himself, would use
>>the cadenza almost like a showcase after the orchestra finish playing,
>>almost like the drummer will do take a solo towards the end of a song in
>>a jazz band concert.  Impulse...Impulse...SPONTANEITY!!!!!!
>
>Well, LvB may have improvised his own, but he carefully wrote them out for
>all us other schmucks to play!

Very true.  This is a typical case of "quod licet Iovi, non licet bovi."
Instructive is his short quarrel with Czerny, who had had the guts to take
too much liberties when playing one of Beethoven's sonatas, at least to the
taste of the composer, who got very angry.  Obviously he began to regret
this the next morning and he wrote an apology letter.  A sentence (my
translation of the original text): "...you should forgive the author that
he prefers to hear his music played as he wrote it down..." Czerny in his
memories (again my translation): "...I had allowed myself in my youthful
frivolity various changings - difficult passages, use of high-pitched
octaves, et cetera..."

Greetings,
Joyce Maier
www.ademu.com/Beethoven