According to Paulinus the Deacon's Vita Ambrosii, Ambrose, at some time within the last three years of his life, after the death of the Emperor Theodosius (d. 395), discovered in a garden outside the walls of Milan the body of Nazarius, with severed head.

The Catholic Encyclopedia states: "Obviously a tradition regarding these martyrs was extant in the Christian community of Milan which led to the finding of the two bodies.

Celsus was entrusted to the care of a pagan lady, who attempted to make him abjure his faith.

Nazarius and Celsus were taken in a ship and thrown overboard, but a storm suddenly arose, frightening the sailors.

[1] Nazarius and Celsus left Trier and reached Genoa, and then returned to Milan, and were arrested again.

[5] This legend, written much later, is without historical foundation and places the martyrdom of Nazarus and Celsus during the persecution of Nero, and describes with many details the supposed journeyings of Nazarius through Gaul and Italy.

The discourse eulogizing the two saints which has been attributed to Ambrose (Sermo lv, in Patrologia Latina, XVII, 715 sqq.)

Paulinus of Nola speaks in praise of Nazarius in his Poema xxvii (Patrologia Latina, LXI, 658).