The first known example of "modern style" graffiti survives in the ancient Greek city of Ephesus (in modern-day Turkey) and appears to advertise prostitution, according to the tour guides of the city. It stands near the long mosaic and stone walkway and consists of a handprint, a vaguely heart-like shape, a footprint and a number. This purportedly indicates how many steps one would have to take to find a lover, with the handprint indicating payment.
Ancient Pompeiian graffito caricature of a politician.The Romans carved graffiti into their own walls and monuments, and examples of their work also exist in Egypt. The eruption of Vesuvius preserved graffiti carved on the walls of Pompeii, and they offer us a direct insight into street life: everyday Latin, insults, magic, love declarations, political consigns. Hadrian's Villa at Tivoli also has several examples. One example has even survived that warns: "Cave Canem", which translates as "Beware of the dog," next to a picture of the dog in question.
However, not only Greeks and Romans learn how to graffiti: the Mayan site of Tikal in Guatemala, also contains ancient examples. Viking graffiti survive in Rome and at Newgrange Mound in Ireland, and Varangians carved their runes in Hagia Sophia in Constantinople. The Ancient Irish inscribed stones with an alphabet called Ogham -- this standard mode of writing may not classify as graffito.
Later, French soldiers carved their names on monuments during the Napoleonic campaign of Egypt in the 1790s.
Art forms like frescoes and murals involve leaving images and writing on wall surfaces. Like the prehistoric wall paintings created by cave dwellers, they do not comprise graffiti, as the artists generally produce them with the explicit permission (and usually support) of the owner or occupier of the walls.