Little is known of her life, and this information was received by private revelation from her. Martyred at about age 14 in the early days of the Church.
In 1802 the remains of a young woman were found in the catacomb of Saint Priscilla on the Via Salaria. It was covered by stones, the symbols on which indicated that the body was a martyr named Saint Philomena. The bones were exhumed, cataloged, and effectively forgotten since there was so little known about the person. An inscription near her tomb read "Peace be with thee, Philomena", along with drawings of 2 anchors, 3 arrows and a palm. Near her bones was discovered a small glass vial, containing the remains of blood. Because it was a popular custom of the early martyrs to leave symbols and signs such as these, it was easily determined that St. Philomena was a virgin and a martyr.
In 1805 Canon Francis de Lucia of Mugnano, Italy was in the Treasury of the Rare Collection of Christian Antiquity (Treasury of Relics) in the Vatican. When he reached the relics of Saint Philomena he was suddenly struck with a spiritual joy, and requested that he be allowed to enshrine them in a chapel in Mugnano. After some disagreements, settled by the cure of Canon Francis following prayers to Philomena, he was allowed to translate the relics to Mugnano.
Miracles began to be reported at the shrine including cures of cancer, healing of wounds, and the Miracle of Mugnano in which Venerable Pauline Jaricot was cured a severe heart ailment overnight. Philomena became the only person recognized as a Saint solely on the basis of miraculous intercession as nothing historical was known of her except her name and the evidence of her martyrdom.
Pope Leo XII granted permission for the erection of altars and churches in her honor. Pope Gregory XVI authorized her public veneration, and named her patroness of the Living Rosary. The cure of Pope Pius IX, while archbishop of Imola, was attributed to Philomena; in 1849, he named her patroness of the Children of Mary. Pope Leo XIII approved the Confraternity of Saint Philomena, and raised it to an Archconfraternity.
Pope Pius X raised the Archconfraternity to a Universal Archconfraternity, and named Saint John Vianney its patron. Saint John Vianney himself called Philomena the New Light of the Church Militant, and had a strong and well-known devotion to her. Others with known devotion to her include Saint Anthony Mary Claret, Saint Euphrasia Pelletier, Saint Francis Xavier Cabrini, Saint John Nepomucene Neumann, Saint Madeline Sophie Barat, Saint Peter Chanel, Saint Peter Julian Eymard, Blessed Anna Maria Taigi, and Venerable Pauline Jaricot.
Her popularity soon became widespread, with her most memorable devotees being St. John Vianney, St. Madeleine Sophie Barat, St. Peter Eymard, and St. Peter Chanel. After being miraculously cured, Ven. Pauline Jaricot insisted that Pope Gregory XVI begin an examination for the beatification of St. Philomena, who was to become known as the "wonder worker". After hundreds of other miraculous cures, she was beatified in 1837.
St. Philomena, who the pope named as the Patroness of the Living Rosary and the Patroness of the Children of Mary, is the only person recognized as a saint solely on the basis of her powerful intercession, although pertinent revelations regarding her life have been recorded. Her relics are now preserved in Mugnano, Italy.
Official website of the Sanctuary of Saint Philomena, Mugnano del Cardinale, Italy
Wikipedia article on St. Philomena