Atella was an ancient Oscan city of Campania, halfway between Naples and Capua; its ruins lie between the towns of Orta di Atella and Sant'Arpino. Atella is not mentioned until the Second Punic War, when, although an independent city striking its own coinage, it was allied with Capua and the other Campanian cities in siding with Carthage after the battle of Cannae. It was occupied by Rome in 210 BC, the chief citizens executed and the survivors enslaved or exiled; the city was refounded as a home for the refugees from Nuceria. In the 1st century BC, Cicero speaks highly of it and appears to have been its patron; it continued into imperial times as a municipium, famed for its traditional scenic performances known as Atellanae. In the slave revolt of Spartacus, the slave army was brought to the city after they defeated Lucius Furius and Lucius Cossinius in Nuceria. Near the city, a fight broke out between the rebels and a Roman force.
The Christian bishopric seated at Atella had its origins in 438 or 439 when Canion and eleven associates from North Africa were either expelled by Gaiseric, the Arian king of the Vandals or fled: ex Africa pulsi vel propria sponte exulantes, in Italian advecti. As Saint Canio he took his place among the saints and martyrs of Capua and of Campania in a mosaic iconography in the Basilica of Saint Prisco in Capua, where his image is identified with his name. His feast is recorded in the martyrologies as 25 May.
The city had been laid waste by the 8th century to such an extent that bishop Leo of Acerenza in Lucania translated the saint's relics to Acerenza, where he became the patron saint. The seat of the bishopric was transferred to the nearby Norman fortress-city of Aversa in 1030. No longer a residential diocese, Atella is today listed by the Catholic Church as a titular see.
The ruins of the city walls, private houses, and many tombs remain, on sites in the comuni of Frattaminore, Orta di Atella, Sant'Arpino and Succivo (these last three together made the comune of Atella di Napoli in the mid‑1900s). Ancient territory of Atella is now represented in the comuni of Caivano, Cardito, Cesa, Frattamaggiore, Grumo Nevano and Sant'Antimo.
- Tabula Peutingeriana; William Smith, ed. A Dictionary of Greek and Roman Geography (1878) s.v. "Atella"
- Livy, ii.61; Silius Italicus, Punica xi.14, noted in Smith 1878.
- Smith 1878.
- Cicero, De leges agr. ii.31, familiar letters
- "Diocese of Aversa". Catholic Encyclopedia. New York: Robert Appleton Company. 1913.
- Annuario Pontificio 2013 (Libreria Editrice Vaticana 2013 ISBN 978-88-209-9070-1), p. 841
- See those communes.