Legalities

So I was working at the office the other day when I started to ponder legal sized paper. Why is it the size it is? Why did it have to be made longer than a standard 8 1/2 X 11 inch sheet of paper? In order to properly store legal files you need to put this special paper in special files that go in special cabinets, sounds like too much special equipment. Maybe that is why lawyers charge so much, it costs them extra to print out and store all those legal documents. Would it be illegal to use non-legal sized paper for a legal document? Ok, I will stop with the lame jokes.