[3] Saint Gregory the Great, in his Dialogues (IV, 12) and Homiliae in Evangelium, speaks of a bishop of Narni named Juvenal, and describes him as a martyr.

[3] The Codex Bernense of the Martyrologium Hieronymianum records his name under May 3 with those of three martyrs of the Via Nomentana: Eventius, Alexander I, and Theodulus.

His legend suggests that he saved Narni from both Ligurian and Sarmatian invaders by calling down a divine thunderstorm.

[3][6] The author of the Life of Pope Vigilius (sixth century) in the Liber Pontificalis states that a monastery founded by Belisarius near Orte was dedicated to Juvenal.

[3][6] The relics of Saint Cassius were built in a restored shrine later known as the Sacello di San Cassio.