when was tune 432 changed to 440 – Google Search

May 13, 2018 – As early as 1885, the Music Commission of the Italian Government declared that all instruments and orchestras should use a tuning fork that vibrated at 440 Hz, which was different from the original standard of 435 Hz and the competing 432 Hz used in France.

Source: when was tune 432 changed to 440 – Google Search