Who decided the proper length for an artist's paint brush?

I'm curious as to why most brushes sold all have handles of a standard length while the brush tip varies. Who decided what the length of the handle would be and how did it become a standard? I'm a professional painter and this question has been plagueing me for years.Who decided the proper length for an artist's paint brush?
Wow, that's really interesting! Haha, I've never thought about that until now..maybe because if the handle was shorter, like a pencil's length, the artist would not be able to see what he was painting too well since his hand would be in the way? Maybe it's just easier for the artist to see what he's doing when he's got a lengthy handle. That's what I think. As for who, I don't know!Who decided the proper length for an artist's paint brush?
I have noticed Oil / Acrylic brushes are a lot longer than Watercolor brushes. (The handles) So I say it might be due to how they are used. Watercolorists work relatively flat and closer to their surface where their counterpart works upright and needs more visual distance as they work. Just my thoughts.
Different artists like working with different handles. I like the longer ones because I can stand farther from the canvas, when people work on chairs close to the canvas I guess they like the shorter ones. It is all on what people buy. If they would not buy one kind or other length would be better than that is what people would buy.
you keep asking these crazy questions you wont get any painting done! I really just think the length was determined so you can grab your brushes out of the jar in case you drop them.