The oldest written mesage in the history of mankind has its roots somewhere in România, in a place named Tărtăria. It dates 5500 years ago, and it represents some not yet understood messages written on clay tablets. Probably it was from a content marketing campaign.
If you ask me, most likely the messages are the try of some guy trying to seduce a girl or to have some sort of a bound between him and her that will go through time.
And in my opinion this is the oldest form of content marketing.
2 „pages” out of the 3 tablets have a hole for a lanyard so that can be worn, and by that we can speculate that the messages are something personal, something private, that had meaning for the person who wear them.