When did the first caveman or woman decide to style their hair? A desire to appear less primitive, more like "Ladies and Gentlemen". Facial hair in particular can be used to speak volumes about a person's character.
I gave myself a broad directory of interesting male moustaches and female eyebrows by surveying paintings, photographs, and statuary from the last 2 thousand years. I picked the most unusual and expressive brows and taches I could find, then I published an edition of 100 books called "Ladies and Gentlemen". Each double page had a male moustache on the left with female eyebrows on the right. The pairings of the two were decided aesthetically, by which moustaches suited which brows.