GRAFFITI. — As the name indicates, graffiti are drawings or writings executed with a hard point on a softer surface, such as wall plaster, terracotta, or even marble or metal. The drawing is characterized by its flat appearance, with almost no relief, though shading and fine details are sometimes used to compensate. The writing is cursive and summary in nature, making it generally difficult to read.
In compensation, however, graffiti tend to express personal sentiments with greater freshness and immediacy. For this reason, the countless graffiti found on almost every wall of Pompeii are of immense value; for the history of Christianity, no less precious are those left by the first Christians on their tombs, the walls of their houses, and especially on the walls of their sanctuaries. Thanks precisely to these inscriptions, it has often been possible to identify venerated martyrs' shrines in the catacombs, for example, the *Memoria Apostolorum* along the Appian Way, where later the basilica of St. Sebastian arose. For the type of such writings cf. CAPITAL, WRITING.