A440 is _entirely_ arbitrary. "French Baroque" A392 is another "standard". In general, standard pitch has been rising for centuries, as orchestra conductors strive for ever brighter sounds. The A440 standard was adopted in 1939 (my daughter's piano is older than that) replacing the A435 standard established in 1859. In general, compositions of Bach, Haydn, Mozart, and Beethoven were originally heard about a semitone lower than they are played today.
Here's whistling at you! Merry Christmas!