Paper sizes
In Germany in the early 1920s, paper sizes were standardized based on a formula set out in 1796 by Georg Lichtenberg, mathematician and philosopher, and further developed early in the 20th century by a chemist, Professor Oswald. The standard formats known and used throughout the world today (ISO 216:1975) were already established in 1923 when everyone began to recognize A, B and C formats.
It only takes a little thought to see how important standard paper sizes are to the international paper market. Machines for manufacturing and cutting paper don't have to deal with too many variants. The packaging and shipping of paper is vastly simplified. Computer printers and copying machines can come in standard configuration. And, paper producers all over the world enjoy important economies of scale.