Christopher Webber replies to me:

>>I consider my ears to be the definitive judge.
>
>Of course the first five notes of the "Bastien" overture coincide with
>Beethoven's Eroica; but is not this one of those classic conversational
>gambits that gets dragged up by the desperate at dinner parties?

It's not the first five notes.  I was so caught up in this debate, that
I went and bought a recording of the overture (Colin Davis -- Mozart
Overtures).  The piece was a lot shorter than I remembered from having
heard it in concert -- less than two minutes.  Although the beginning of
the overture immediately reminds me of Eroica, it's not close enough for me
to say, "ah, that's the Eroica theme!".  However, a few bars later I heard
the first eight notes of the Eroica theme, played with the same rhythm,
tempo (approximately) and accompaniment from the violins (i.e.  1/8 note
chords).  The time signature of the Bastien overture is 3/4 (same as
Eroica), and the key sounds like G major (which is not the same as Eroica).
I used my ears to determine this, so please beware.  It's possible that the
violins that I heard were really tubas.

I'm sorry to be so stubborn.  Of course, resolving this debate is not a
matter of life and death.  However, I still must insist that the similarity
is more than coincidence, despite some peoples' (on this list) claim that
Beethoven never heard Mozart's Bastien.

Mike