Before written music, how did bellmakers determine the tones to use in constructing the bells for the ancient cathedrals of Europe? How do those tones match up with western music at this time?

Do eastern bells, say from Sri Lanka, or Japan, or Korea, or China, match up with notes in western music? Or are they on-key for their own system but off-key for westerners?

Is there some geometric system or rule that demonstrates those distances between sounds that create harmony? Are there ways to visually demonstrate the relationships? I'm sure there must be already - given the wonderful software developed by musicians and techies. I really enjoy 'seeing' music. I'd like to be able to sketch sound, to see music in different ways, learn more about the spatial relationships, but am not learned in these areas.

I've been in church services where the ringing of altar bells seems to break up a kind of stagnant space, and carry in fresh air, so to speak. I've heard some eastern bells that when rung at the same time are almost too powerful to bear, their unusual harmonies are so beautiful.