Who created fair use?

Answer 1

The first related decision was in Gyles v Wilcox in 1740, which ruled that an abridgment of a book (which requires editorial decisions, education, and judgment) was not infringing. This "fair abridgment" idea carried forward into the various "fair dealing" and "fair use" laws around the world.

Answer 2

In the US, it is generally traced to an 1841 decision in Folsom v Marsh. Although it was widely accepted as common law, it wasn't included in the copyright act until 1976.