"I have come to cast fire upon the earth, and what will I but that it be kindled?"
St. Luke 12:49
Among the disciples of the Apostles, in the primitive age of Saints, this holy virgin shone like a bright star in the Church. She lived when Christians were more solicitous to live well than to write much; they knew how to die for Christ, but they did not compile long books in which vanity often has a greater share than charity, and thus no particular account of her actions has been handed down to us. But how eminent her sanctity was we may judge from the luster by which it was remarked amid Apostles, prophets, and martyrs.
Saint Petronilla is the daughter of the Apostle Saint Peter. We know from the Gospel that Saint Peter was married before his call from Christ, and Saint Clement of Alexandria assures us that his wife, Saint Perpetua, attained to the glory of martyrdom. On that occasion, Peter himself encouraged her, bidding her to remember Our Lord.
Although some authors are not certain whether Saint Petronilla was more than the spiritual daughter of that Apostle, the Bollandists assure us that she was indeed the child of the two holy Saints and martyrs. She dwelt in Rome also, and vowed her virginity to Christ. When suitors presented themselves, she begged her Lord to take her from this world, and her request was granted. She was buried on the road to Ardea, where in ancient times a cemetery and a church bore her name. Her relics have been since 1606 in a chapel dedicated to her in the Basilica of Saint Peter.
Reflection. With the Saints, the great end for which they lived was always present to their minds, and they thought every moment lost in which they did not make some advances toward eternal bliss. How will their example condemn, at the last day, the trifling frivolities and the greater part of the conversation and employments of the world which aim at nothing but present amusement, and forget the only important affair that of eternity!
Les Petits Bollandistes: Vies des Saints, by Msgr. Paul Guérin (Bloud et Barral: Paris, 1882), Vol. 6; Little Pictorial Lives of the Saints, a compilation based on Butler's Lives of the Saints and other sources by John Gilmary Shea (Benziger Brothers: New York, 1894).