She made an unsuccessful attempt at flight, whereupon Alexander had her removed to the castle of S.Angelo.However, certain French gentlemen in the service of the one who was bent on her destruction--especially Ivo d'Allegre--interceded for her; and the Pope, after she had spent a year and a half in captivity, allowed her to choose Florence for her asylum.
He himself commended her to the Signory in the following letter: UNTO MY BELOVED SONS: Greeting and the Apostolic Blessing.
Our beloved daughter in Christ, the noble lady Catarina Sforza, is on her way to you.

She, as you are aware, having for good reasons been held a prisoner by Us for a time, has again become the object of Our mercy.

We, according to Our custom and to Our pastoral duties, have not only exercised mercy with regard to this Catarina, but also, so far as We with God's help were able, have looked with paternal solicitude after her welfare; therefore We deem it proper to write you for the purpose of commending this Catarina to your protection, so that she, having full confidence in Our good will towards you, and returning, so to speak, into her own country, may not be deluded in her expectations and by Our recommendation.

We, therefore, shall be glad to learn that she has been well received and treated by you, in gratitude to her for having chosen your city for her abode, and owing to your feelings toward Us.

Given at Rome, in S.Peter's, under the Apostolic seal, July 13, 1501.