I retuned this from A=440Hz down to the Scientific Pitch C=256Hz
"Since France has adopted a standard pitch, I advised that the example should also be followed by us; and I formally requested that the orchestras of various cities of Italy, among them that of the Scala [Milan], to lower the tuning fork to conform to the standard French one.
If the musical commission instituted by our government believes, for mathematical exigencies, that we should reduce the 435 vibrations of French tuning fork to 432, the difference is so small, almost imperceptible to the ear, that I associate myself most willingly with this.
It would be a grave, extremely grave error, to adopt, as proposed from Rome, a standard pitch of 450!!!
I also am of the opinion with you that the lowering of the tuning in no way takes away the sonority or liveliness of the execution; but gives on the contrary, something more noble, of greater fullness and majesty that the shrieks a too high tuning fork could give.
For my part, I would like a single tuning to be adopted in the whole musical world. The musical language is universal: Why then would the note which has the name ‘A’ in Paris or Milan have to become a B-flat in Rome?" -G. Verdi, 1881