St. Petronille was a blessed virgin martyr with little known about her life and death. She is reputed to be the daughter of St. Peter but that also is interpreted as a spiritual daughter, not biological. Stories tell of her being cured of palsy by St. Peter.

She was a noble woman of the Domitilla family who was a Christian convert in either the 1st or late 3rd Century Rome. Petronille refused marriage to Count Flaccus desiring instead to devote herself to Christ. One version has him threatening to kill her. She prayed and fasted for three days, then died in bed. Another version has her persecuted and killed for refusal to betray her faith. 4th century Christian martyrologies include her as a martyr. Her image generally is displayed as a young woman with a palm or keys of St. Peter in one hand and book in the other.

Patron saint of mountain travelers and hospitality, Petronille is honored with a feast day on May 31. Her remains were interred in the Domitilla catacombs, then entombed in a church there. They were transferred to St. Peter’s Basilica in Rome, now called the Chapel of St. Petronilla.