Then the Governor, being incensed against her, gave her the alternative of either sacrificing to the gods, or being submitted to the torture; and as she remained firm in the faith, she was buffeted and sent back to prison. The next day she was brought forth, and, because her resolution was still unshaken, she was stretched on the rack and tortured with pieces of white-hot metal. Then her breasts were cut off. When Agatha received this injury she cried out to Quintianus, "Cruel tyrant, art thou not ashamed to do this to me, having thyself suckled at a mother's breast?" She was remanded again to prison and put in irons. That night an old man, who called himself an Apostle of Christ, came to her, and healed her wounds. The following day she was brought for the last time before the Governor. Her constancy was unmoved, and she was rolled on sharp potsherds and live embers.
At that time the whole city was shaken with a great earthquake, and two of the Governor's dearest friends, Silvinus and Falconius, were killed by falling walls. The townspeople were in an uproar, and Quintianus, in fear of a riot, ordered Agatha, who was half dead, to be carried back to prison quietly. Then she made the following prayer: O Lord, who hast been my Keeper from my childhood, who hast taken from me all love for this present world, who hast strengthened me so that I am more than conqueror over the cruelty of the executioners, receive my spirit. With these words she passed to heaven, finishing her testimony on the 5th day of February. Her body was buried by the Christians.
Agatha is buried at the Badia di Sant'Agata, Catania. She is listed in the late 6th-century Martyrologium Hieronymianum associated with Jerome, and the Synaxarion, the calendar of the church of Carthage, ca. 530. Agatha also appears in one of the carmina of Venantius Fortunatus. Two early churches were dedicated to her in Rome, notably the Church of Sant'Agata dei Goti in via Mazzarino, a titular church with apse mosaics of ca. 460 and traces of a fresco cycle, overpainted by Gismondo Cerrini in 1630. In the 6th century the church was adapted to Arian Christianity, hence its name "Saint Agatha of Goths", and later reconsecrated by Gregory the Great, who confirmed her traditional sainthood. Agatha is also depicted in the mosaics of Sant' Apollinare Nuovo, Ravenna, where she appears, richly dressed, in the procession of female martyrs along the north wall. Her image forms an initial I in the Sacramentary of Gellone, from the end of the 8th century.
Agatha is the patron saint of bell-founders because of the shape of her severed breasts, and also of bakers, whose loaves were blessed at her feast day. More recently, she has been venerated as patron saint of breast cancer patients.
She is claimed as the patroness of Palermo. The year after her death, the stilling of an eruption of Mt. Etna was attributed to her intercession. As a result, apparently, people continued to ask her prayers for protection against fire.