Putting aside that notes don't really have to be in tune to be notes, this is not where A=440hz originated.
Correction: upon further research, this is where 440hz originated. However, it was not the original standard (or where musical notes come from), and I find the history interesting, so I'm going to post it anyway.
Tuning used to be based off of whatever instrument was not easily tunable (the piano or organ), or some other instrument (oboe?) if there was none. For much of musical history tuning was significantly lower than A=440, albeit with a lot more variation; however, it tended to rise[0][1] in order to create a more brilliant-sounding timbre (particularly in larger venues), especially among instrumental pieces. This led to some contention, especially with vocalists who found the increasingly-high notes more and more difficult to sing. There were several efforts to readjust tuning to something more reasonable, but ultimately none of them worked for long.
Frequency was actually orignically standardized in Article 282, section 22 of the Treaty of Versailles.[2] This may not make a lot of sense at initial glance, but when thinking about it as how good orchestras sound, it does make some sense as an economic policy
This is where I originally messed up, though. The Treaty of Versailles references something else (which I don't have a link for), but which, per [1], standardizes to... 435hz. But again this crept up, and apparently the US and UK did some shenanigans with interpreting it (the UK changed the temperature to get it to 439hz, I haven't found out precisely what the US did), and there was again some debate. Some people gave up and standardized with the UK to 440hz, some stayed at 435, and eventually the ISO did step in and standardized again on 440.
So we may all be breaking international law by tuning to 440hz.
Correction: upon further research, this is where 440hz originated. However, it was not the original standard (or where musical notes come from), and I find the history interesting, so I'm going to post it anyway.
Tuning used to be based off of whatever instrument was not easily tunable (the piano or organ), or some other instrument (oboe?) if there was none. For much of musical history tuning was significantly lower than A=440, albeit with a lot more variation; however, it tended to rise[0][1] in order to create a more brilliant-sounding timbre (particularly in larger venues), especially among instrumental pieces. This led to some contention, especially with vocalists who found the increasingly-high notes more and more difficult to sing. There were several efforts to readjust tuning to something more reasonable, but ultimately none of them worked for long. Frequency was actually orignically standardized in Article 282, section 22 of the Treaty of Versailles.[2] This may not make a lot of sense at initial glance, but when thinking about it as how good orchestras sound, it does make some sense as an economic policy
This is where I originally messed up, though. The Treaty of Versailles references something else (which I don't have a link for), but which, per [1], standardizes to... 435hz. But again this crept up, and apparently the US and UK did some shenanigans with interpreting it (the UK changed the temperature to get it to 439hz, I haven't found out precisely what the US did), and there was again some debate. Some people gave up and standardized with the UK to 440hz, some stayed at 435, and eventually the ISO did step in and standardized again on 440.
So we may all be breaking international law by tuning to 440hz.
[0] https://en.wikipedia.org/wiki/Concert_pitch#Pitch_inflation
[1] https://www.youtube.com/watch?v=BzznBt8tVnI
[2] https://en.wikisource.org/wiki/Treaty_of_Versailles/Part_X#A...