The Christian bishopric with see at Atella (or rather modern Orta di Atella) dates back, according to recent hagiography, to a bishop named Canio, martyred under the Roman Emperor Diocletian in about 300 (traditionally 313 AD). The Greek legend of Saint Januarius mentions a bishop of Atella as one of those who accompanied the relics of that saint to Naples. A later bishop of Atella named Elpidius built a church over the tomb of Canio; in the 9th century, the cathedral of Atella was dedicated to Bishop Elpidius as Saint Elpidius. In two of his letters, Pope Gregory the Great (592 and 599) mentions a Bishop Importunus of Atella; the second letter announces that Bishop Importunus is dead, and a successor should be elected.