Within the Martyrology, she is accounted accordingly on this day: "At Catania in Sicily, the birthday of St. Agatha, Virgin and Martyr, who in the time of the Emperor Decius, under the judge Quinctian, after buffets and imprisonment, racking, the twisting of her limbs, the cutting off of her breasts, and torture by being rolled upon sherds and burning coals, at last died in prison while in prayer to God."
V.L. Kennedy, CSB, in his study, The Saints of the Canon of the Mass (published in 1963 as part of the "Studi di Antichita Cristiana" imprint of the Pontifico Istituto di Archeologia Cristiana) had this to say of St. Agatha:
The cult of this saint seems to have passed to Rome at the end of the fifth or beginning of the sixth century. Pope Symmachus built in her honor a church on the Via Aurelia outside the city. However the real development of her cult seems to have begun only with Gregory the Great (590-604). It was he who dedicated to her the ancient church of the Goths in the Subura district of Rome; this church had been constructed by Flavius Ricimer, who was Consul in the year 459...
There are reasons for believing that Gregory the Great had a very special devotion to St. Agatha. In his letters he speaks of a Monastery in Sicily dedicated to SS. Maximin and Agatha, which he seems to have founded himself. In another letter to John, Bishop of Surrentinum in Caprea, he orders the establishment of a sanctuary containing her relics in a local monastery...
...it is not surprising to be told by St. Aldhelm that Gregory himself placed the name of Agatha and Lucy in the Roman Canon... The question arises as to the value of the testimony of St. Aldhelm in this particular... [but] it is beyond dispute that Aldhelm knew the Roman traditions of his day, and when he writes that Gregory placed our saints in the Canon, he is worthy of the highest credence.
A custom associated with the Feast of St. Agatha is the blessing of bread. The Catholic Encyclopedia notes that "in some places bread and water are blessed during Mass on her feast after the Consecration, and called Agatha bread." Josef Jungmann mentions this as well in The Mass of the Roman Rite (see ii, p. 260), as does Archdale King in The Liturgy of the Roman Church:
A York MS. (c. 1425)... has a blank space immediately before the words per quem haec omnia, indicating that on certain occasions prayers were inserted here. A very ancient Vatican MS, and a sacramentary of Corbie supplies a blessing of the paschal lamb on Easter Day... The Missal of Narbonne (1528) has a blessing of bread on the feast of St. Agatha (5 February), and in the archdiocese of Gnesen-Poznan in Poland, churches still have the privilege of hallowing bread and water on this day. (p.342)
Martyris ecce dies Agathae
An Ancient Hymn in Honour of St. Agatha
Now dawns the feast of Agatha,
The illustrious virgin and martyr;
Christ has espoused her to himself,
And crowns her with a double crown.
Of noble race and beauteous form,
More illustrious still by deeds and by faith,
She sets no value at all on earthly well-being,
But binds to her heart the commands of her Lord.
Stronger by far than her cruel tormentors,
She yielded her fair limbs to the terrible scourgings,
And proved the great fortitude deep in her bosom,
By enduring in her breasts the bitterest of tortures.
To her the dungeon was a place of delight,
And thither came Peter the Shepherd to comfort his lamb.
Thus encouraged and burning with still greater zeal,
She joyfully ran the ever new torments to meet.
The pagan mob fleeing the peril of Etna's fierce flames,
By Agatha's power is effectively aided.
And those who take pride in their title of faithful
From unchastity are also preserved by the saint.
Now that as a bride she shines resplendent in heaven,
May she beg the Lord's mercy on those who are wretched,
And whilst here below we celebrate her feast,
May she be propitious to all who praise her great name.
* * *
Sant'Agata in Trastevere
Sant'Agata dei Goti
