Febronia was an orphan who grew with her aunt Brienne, a Christian devotee. On 25th June 305, during the persecutions of Christians ordered by Emperor Diocleziano, she chose martyrdom and suffered from atrocious tortures. She was tied at a pole to be flagellated and scratched with iron brushes, then tortured with the rack; her teeth were pulled out, her breasts cut, and then also her hands and feet were cut. At the end she was beheaded. The church of San Carlo ai Catinari preserves her skull, moved here after the Church of San Paolo was demolished to build Palazzo Chigi. The relic is visible enshrined in "Fenestella confessionis" on the main altar.