Sometimes I am assailed by the strangest doubts: how were measuring cups invented?
It is actually not as easy as I thought to find an answer (probably because nobody bothers, but you already know I am that boring as a person).
I found out that Fannie Farmer decided to standardize them into specific measurements. It happened circa 1879 in Boston, USA. The poor lady was left limp as a child and made cooking her reasons of life. She published the Boston cooking school cook book, which has been so popular that is still in print nowadays.
Yet although Ms. Farmer did standardize the measuring units, to give consistency to recipes, I believe she was working with something already in use.
Looking further back in history is though impossible (at least in google). I’ve only found a couple of sources telling that probably cup measurements dated back to the 1700 and probably stemmed by Afro American cooks, that during slavery used chipped bone china left by the owners in order to prepare their recipes.