[2] After studying law, he traveled to Rome, he served a governor of Velletri and then became referenda of the Apostolic Signatura.
In 1536,Ignatius and his first companions were in Venice and made a vow of poverty and chastity in the hands of the nuncio.
In August 1542 he traveled to Nuremberg with Bishop Otto Truchsess von Waldburg to present the Imperial Diet with the papal bull Initio nostri huius pontificatus (issued 22 May 1542) calling the Council of Trent, set to begin on 1 November 1542, and to attempt to convince German and Hungarian bishops to attend the council.
He received the red hat and the titular church of San Martino ai Monti on 10 May 1549.
[2] During this mission, he was accompanied by his nephew Giambattista Castagna, future Pope Urban VII, who served as a datary.
On 18 September 1551 Pope Julius III gave him the Palace of Sant'Apollinare alle Terme Neroniane-Alessandrine (though not the church property) ad vitam.