What we know about these saints came to us from St. Ambrose, Bishop of Milan. In 395 A.D. St. Ambrose discovered the body of St. Nazarius, with severed head, along with a vial of his blood still as fresh as the day it was spilled, in a garden outside the city gates. St. Ambrose carried the body in procession to bury in the city's Basilica of the Apostles. In the same garden he also discovered the body of St. Celsus, and likewise had the body taken to the same basilica.
Miracles occurred in the church at the presence of the relics of these two holy martyrs. According to one account, St. Nazarius was the son of St. Perpetua, the child she bore just prior being executed for her faith. Celsus was a youth given to the care of St. Nazarius by the boy's mother, who desired for the saint to teach her son the Christian faith. The two traveled and preached the Gospel together zealously before being tortured and executed in Milan.
