I’ve wondered how we know that 415 was a Baroque A. And now I’ve read this:
Haydn’s tuning fork does indeed exist. So does Handel’s.
Ah. Well there you go! Haydn’s fork is 422.5.
You can read more than you ever needed to know about tuning. Or maybe it is exactly what you needed to know.
I’ve been told that San Francisco Symphony tunes to A-441. I tune Opera San José to 440. Anyone else care to share what they tune to? (Notice I say we tune to a certain pitch. I’m not going to claim it stays there, although I do my best.)
Now I want to know if Beethoven’s metronome was really accurate. I did see this 1987 article but it doesn’t question the accuracy of the metronome so I guess that’s not an issue.