When somebody asks me for my favourite fact, I tend to pull out a very old one I heard and factchecked a long time ago:

Did you know that the World War I Treaty of Versailles signed in 1919, also dictates what Concert Pitch Germany has to tune to?

Let's go ahead and fact check it again, this time with a paper trail... byte trail.

The Claim

Supposedly it was a byproduct of Germany falling behind on their international treaties during the war. The Allies demanded that in addition to all the other boring peace stuff, Germany has to accept all the treaties that they weren't part of, since well, international law doesn't cease to progress just because of an armed conflict.

As to why this other treaty existed, the reasoning goes that as craftsmanship improved around musical instruments, they could be tuned to ever higher notes. High notes then becoming a sign off high-quality pushing people to actually tune them high, kind of forgetting that there's an instrument that you can't easily tune, which is the human voice. So singers don't destroy their bodies the proliferation of some standardisation began, from which this eventually sprung.

FactCheck

I first tried skimming Part 15. miscellaneous provisions, don't see it in there. However I did realise that it could be a searchable fact and in fact I did come accross an article. This cites no sources, however it gives us a valuable tool, the year of the original treaty - 1885.

And sure enough, searching "Versailles 1885" was enough, under Part 10. economic clauses and there it is:

SECTION II.

TREATIES.

ARTICLE 282.

From the coming into force of the present Treaty and subject to the provisions thereof the multilateral treaties, conventions and agreements of an economic or technical character enumerated below and in the subsequent Articles shall alone be applied as between Germany and those of the Allied and Associated Powers party thereto:

...

(22) Convention of November 16 and 19, 1885, regarding the establishment of a concert pitch.

Btw, if you're wondering why the page number jumps from 335 to 337, that is because every other page is the same as the previous one but in french. Fascinating that the two languages are styled so differently.

While looking for this I also encountered the Avalon project, which seems to archive all manners of historical documents regarding law. Though this treaty is out of their purview so they don't have it, shame. Then there's the Library of Congress, section which only has treaties relating to America I think? Well they don't have my treaty at least.

I found something that may have more information, an article called "Musical Pitch and International Agreement", however it is paywalled on both JSTOR and Cambrdige University Press and my Uni doesn't have access.

I think I need to conclude this for now, so yes, the claim is true, however the reasoning behind and actual text of the original treaty is still lost to me and therefore that part is still hearsay. Anyways, glad I wasn't spreading downright hoaxes, I will include the level or legitimacy when I share this in the future, and you should do that to.