In that case, it's fair to say that classical music conformed to the previous tuning standards. @Longy tells me that 528 is the frequency of love. (I admit I never checked that)

Before classical music (baroque and further back) tuning was also pure and not even temperment tuning. Modern pianos and guitars would be considered out of tune by those past standards.

Very interesting. I've always looked at the conductor and thought no-one in the orchestra is looking at them. Yet, Standing there at the end taking all nthe credit for waving his little sticks.