Beatles song based on Beethoven?
The Beatles cheerfully sang 'Roll Over Beethoven' in their pre-fame stage show. The Chuck Berry anthem also appears on their second album. But if Ludwig was not safely out of copyright, his legal team would most likely have a solid royalties claim.
In one of his last interviews, John Lennon revealed how the great German composer provided direct inspiration:
I was lying on the sofa in our house, listening to Yoko play Beethoven's - Moonlight Sonata, on the piano. Suddenly I said, 'can you play those chords backwards'.
The Beatles version retains the key and key change, plus the pattern of arpeggios. Lennon also added some bass notes and of course and a lyric which he claimed was 'clear, no bullshit, no imagery, no obscure references.'
You won't find that kind of language in Fidelio but there is arguably a similarity of intent across the centuries.