What was the first graffiti?

Given the deep and universal human need to personalize things and generally leave evidence of their presence, I was curious what the first example of graffiti? That is, where was the first informal message written on a public place (and what did it say)?

Kilroy was here?

Why the ten commandments of course!

Daniel 5:

Those are Johnny-come-latelies. Paleolithic cave art would take the prize, I think, but I could be mistaken.

The Lascaux Cave Drawings? 15,000 BCE.

Or did you want a written message? If so, I nominate “Romanes eunt domus.”

More to the point, there wass graffiti in ancient Egypt and Rome.

And some of it was exactly what you would expect.

Porn in Ancient Rome

Good old Harpocras. Wonder if he was an ancestor. {Inside joke.}