Graffiti , the term in common usage among archaeologists to designate a class of rude inscriptions scratched on the walls of ancient monuments, generally sepulchral, as distinguished from the formal inscriptions engraved on the tombs of the deceased. The inscriptions of this order traced by pilgrims, between the fourth and ninth centuries, on the walls of the galleries, proved invaluable to De Rossi and later archologists in their explorations of the Roman catacombs. At an early stage in his career De Rossi realized the importance of these graffiti. Their absence from the walls of a gallery signified that there was nothing of importance in the vicinity, whereas, on the other hand, their presence meant that the explorer was in the immediate neighborhood of an important crypt or other sepulchral monument which once contained the relics of a martyr. Here it was: that a pious pilgrim of old, before leaving the venerated tomb, would take advantage of the occasion to scratch on the adjoining wall his name, with sometimes the date of his visit, or a pious exclamation or prayer to the saint, as, e.g., that near the papal crypt of the catacomb of St. Callistus: “Sancte Suste in mente habeas in orationes tuas Aureliu Repentinu” (Saint Sixtus, remember in thy prayers Aurelius Repentinus). Outside the catacombs the famous caricature of the Crucifixion found in the imperial palace on the Palatine is accompanied by a graffito stating that the (supposed) Christian page, Alexamenos, is adoring his God, while, in a chamber adjoining, a second inscription of the same class proclaims Alexamenos a Christian (Alexamenos fidelis). In 1897 some Christian graffiti were discovered on the columns of the temple of Antoninus and Faustina, intermingled with pagan inscriptions of the third and fourth century. The great necropolis of the oasis in the Libyan desert also contains a number of interesting Christian graffiti (Kaufmann, Handbuch der christl. Arch., 256). Graffiti are also found on ancient Christian altars of the fifth and later centuries (Le Blant, Inscriptions. Chretiennes de la Gaule).
MAURICE M. HASSETT