From Butler's Lives of the Saints:
THE cities of Palermo and Catana, in Sicily, dispute the honour of her birth; but they do much better who, by copying her virtues, and claiming her patronage, strive to become her fellow-citizens in heaven. It is agreed that she received the crown of martyrdom at Catana, in the persecution of Decius, in the third consulship of that prince, in the year of our Lord 251. She was of a rich and illustrious family, and having been consecrated to God from her tender years, triumphed over many assaults upon her chastity.
Quintianus, a man of consular dignity, bent on gratifying both his lust and avarice, imagined he should easily compass his wicked designs on Agatha’s person and estate by means of the emperor’s edict against the Christians. He therefore caused her to be apprehended and brought before him at Catana. Seeing herself in the hands of the persecutors, she made this prayer: “Jesus Christ, Lord of all things, you see my heart, you know my desire-possess alone all that I am. I am your sheep, make me worthy to overcome the devil.” She wept, and prayed for courage and strength all the way she went.
On her appearance, Quintianus gave orders for her being put into the hands of Aphrodisia, a most wicked woman, who, with six daughters, all prostitutes, kept a common stew. The saint suffered in this infamous place assaults and stratagems against her virtue infinitely more terrible to her than any tortures or death itself. But placing her confidence in God, she never ceased with sighs and most earnest tears to implore his protection, and by it was an overmatch for all their hellish attempts the whole month she was there. Quintianus, being informed of her constancy after thirty days, ordered her to be brought before him. The virgin, in her first interrogatory, told him that to be a servant of Jesus Christ was the most illustrious nobility and true liberty.
The judge, offended at her resolute answers, commanded her to be buffeted and led to prison. She entered it with great joy, recommending her future conflict to God. The next day she was arraigned a second time at the tribunal, and answered with equal constancy that Jesus Christ was her life and her salvation. Quintianus then ordered her to be stretched on the rack, which torment was usually accompanied with stripes, the tearing of the sides with iron hooks, and burning them with torches or matches. The governor, enraged to see her suffer all this with cheerfulness, commanded her breast to be tortured, and afterwards to be cut off. At which she made him this reproach: “Cruel tyrant, do you not blush to torture this part of my body, you that sucked the breasts of a woman yourself? “He remanded her to prison, with a severe order that neither salves nor food should be allowed her.
But God would be himself her physician, and the apostle St. Peter in a vision comforted her, healed all her wounds,. and filled her dungeon with a heavenly light. Quintianus, four days after, not the least moved at the miraculous cure of her wounds, caused her to be rolled naked over live coals mixed with broken potsherds. Being carried back to prison, she made this prayer: “Lord, my Creator, you have ever protected me from the cradle; you have taken me from the love of the world, and given me patience to suffer: receive now my soul.” After which words she sweetly gave up the ghost. Her name is inserted in the canon of the mass in the calendar of Carthage, as ancient as the year 530, and in all martyrologies of the Latins and Greeks. Pope Symmachus built a church in Rome on the Aurelian Way under her name, about the year 500, which is fallen to decay.
St. Gregory the Great enriched a church which he purged from the Arian impiety with her relics, which it still possesses. This church had been rebuilt in her honour by Ricimer, general of the Western Empire, in 460. Gregory II built another famous church at Rome, under her invocation, in 726, which Clement VIII gave to the congregation of the Christian doctrine. St. Gregory the Great ordered some of her relics to be placed in the church of the monastery of St. Stephen, in the Isle of Capreae, now Capri. The chief part, which remained at Catana, was carried to Constantinople by the Greek general, who drove the Saracens out of Sicily about the year 1040; these were brought back to Catana in 1127, a relation of which translation, written by Mauritius, who was then bishop, is recorded by Rocci Pyrrho and Bollandus. The same authors relate in what manner the torrent of burning sulphur and stones which issue from mount Aetna, in great eruptions, was several times averted from the walls of Catana by the veil of St. Agatha, (taken out of her tomb,) which was carried in procession. Also that through her intercession, Malta (where she is honored as patroness of the island) was pre served from the Turks who invaded it in 1551. Small portions of relics cf. St. Agatha are said to be distributed in many places.
The perfect purity of intention by which St. Agatha was entirely dead to the world and herself, and sought only to please God, is the circumstance which sanctified her sufferings, and rendered her sacrifice complete. The least cross which we bear, the least action which we perform in this disposition, will be a great holocaust, and a most acceptable offering. We have frequently something to offer-sometimes an aching pain in the body, at other times some trouble of mind, often some disappointment, some humbling rebuke, or reproach, or the like. If we only bear these trials with patience when others are witnesses, or if we often speak of them, or are fretful under them, or if we bear patiently public affronts or great trials, yet sink under those which are trifling, and are sensible to small or secret injuries, it is evident that we have not attained to true purity of intention in our patience; that we are not dead to ourselves. We profess ourselves ready to die for Christ, yet cannot bear the least cross or humiliation. How agreeable to our divine spouse is the sacrifice of a soul which suffers in silence, desiring to have no other witness of her patience than God alone, who sends her trials; which shuns superiority and honours, but takes all care possible that no one knows the humility or modesty of such a refusal; which suffers humiliations and seeks no comfort or reward but from God. This simplicity and purity of heart; this love of being hid in God, through Jesus Christ, is the perfection of all our sacrifices, and the complete victory over self-love, which it attacks and forces out of its strongest intrenchments: this says to Christ, with St. Agatha, “Possess alone all that I am.”