6000 years ago in cuneiform on stone

5K years BP is pushing it, and though there are examples of a semi-alphabetic cuneiform being carved into stone (some Old Persian inscriptions of Darius, ca. 6th century BCE), it was developed for writing on clay tablets. Many tablets have been discovered because the buildings in which they were stored were burned during wartime and the tablets were fired into clay bricks.

Ceci n'est pas un seing.