ATELLA. — Ancient episcopal see in Campania, between Naples and Capua, whose ruins lie within the territory encompassed by the villages of S. Arpino, Grupo, and Pomigliano d'A. A number of bronze coins, dating from after 250 B.C., and painted vases provided evidence of the Samnite civilization of A., which, after being subjugated by the Romans, rebelled following the battle of Cannae, but was punished by extermination and the abolition of its political and territorial existence. In 63 B.C. it reappears among the most important cities of Campania. A. gave its name to theatrical performances of Greek importance, or at least of Greek influence through the Oscans, at the beginnings of Latin theater: « Fabulae atellanae ».
The first testimony of a certain date concerning the episcopal see of A. is provided by s. Gregorio Magno, who, in two letters of 592 (Registr., II, ep. 16) and 599 (Registr., IX, ep. 142), mentions an Importunus, bishop « Atellanae civitatis »; but its origins are undoubtedly more remote, since the Martyrologium Hieronymianum records, under 25 May, the deposition in A. of a martyr named Canione. A Passio s. Canionis (BHL, 1541) informs us that Canione was a bishop and suffered martyrdom in A.; it also relates that a bishop of A., named Elpidio, built a basilica over the martyr’s tomb. In another Passio (BHL, 2520 b), Elpidio is described as a contemporary of Pope Siricius (384–99) and the emperor Arcadius (395–408). In the ninth century, the cathedral of A. was dedicated to a s. Elpidio who must be identical with the bishop mentioned above. During the Lombard invasion, the episcopal see of A. declined; the last bishop known to us is Eusebio, who signed the acts of the Lateran Council held under Martino I in 649 (Mansi, X, p. 867). In 1049 Pope Leone IX restored the bishopric of A., establishing its new Aversa (v.), recently founded by the Norman prince Roberto il Guiscardo.