Standardization question

Who defined the standard width for toilet paper, and when?

Clearly at this point the standard is self-sustaining, but back in the early years of bathroom hygiene this cannot have been the case. Also, I find it curious that it’s an international standard. I mean, the USA has to differ from the rest of the world in practically every other field of human endeavor, but the toilet paper is the same width here as in every other country I’ve visited.