The most authoritative testimony regarding this miracle is found in the Bull Fraternitas tuae (March 13, 1228) written by Pope Gregory IX in response to Bishop Giovanni V of Alatri. The text reads: “Gregory, Bishop and Servant of the Servants of God, to Venerable Brother Bishop of Alatri, greetings and Apostolic blessing. We have received your letter, dearest brother, in which you informed us of a certain young woman misguided by an evil woman, who, after having received from the priest the Most Holy Body of Christ, held the Sacred Host in her mouth until the right moment to conceal the Holy Eucharist in a cloth.
After three days, she discovered the same Body which she had received in the form of bread transformed into flesh, as everyone has been able to verify with their own eyes. Because both women have humbly revealed this to you, you desire our opinion regarding the punishment that should be imposed upon them.
First, we give thanks with all our strength to Him Who, though He always operates in marvelous ways, in this case repeats miracles and produces new wonders so that He calls to sinners, converts evildoers and confounds heretics while strengthening faith in the truth of the Catholic Church, sustaining hope and reigniting charity.
Thus, dearest brother, by means of this apostolic letter, we dispose that you inflict a milder punishment on the young woman, whom we hold to have done this more from weakness than malice, especially because it can be believed that she has sufficiently repented in confessing her sin. To the instigator, who with her perversion pushed the young woman to commit sacrilege, apply those disciplinary measures that we believe opportune to leave to your judgment. She should also visit the nearest bishop so that she can humbly confess her crime, imploring pardon with devout submission.”