Apostolic delegate in Spain
On 19th July 1524 Pope Clemente VII informed Castiglione that he intended to send him to Spain, as apostolic nuncio at he court of the Emperor Charles V, with the mission of dealing with matters regarding “non solo della Sede Apostolica, ma dell’Italia e di tutta la Cristianità” (not only the Vatican, but of Italy and the whole of Christendom). Baldassarre begged leave of the Marquis of Mantua, Federico Gonzaga, and the Pope received his acceptance.
Castiglione stayed in Rome from August to September. On behalf of Charles V he discussed with Lodovico di Canossa, spokes man fro the King of France, Frances I, important diplomatic issues, intending to verify whether the was the possibility of a truce. Bit such attempts at avoiding war turned out to be useless.
On 5th October he left Rome for Mantua. He was accompanied by the poet and architect Giulio Romano, who, as Baldassarre had promised to Federico Gonzaga, was going to enter into the service of the court of Mantua. Saying goodbye to his family, especially his mother, and his children, and the official visits before his departure, kept him busy for a few weeks that he spent between Mantua and Casatico.
Then, in November and December, he stopped of in various places in Lombardy, (Milan, Pave, Crimean), as a neutral ambassador, to meet the Duke of Milan, the Spanish Viceroy and the King of France, who is aiming at controlling the whole of northern Italy. But his diplomatic activities, aimed at diverting a recourse to arms, was immediately invalidated by secret by agreements that, without him knowing, Clemente VII started making secretly directly with Frances I.
On25th December he was in Milan, on 26th at the Certosa di Pavia; then, passing through Turin and Susa, he arrived around the 10th January 1526 in Lyon, from where he wrote to Cardinal Giovanni Salviati a letter full of bitter presentments, caused by the sad and unreasonable behaviour of the Pope. From France he went to Barcellona, then to Saragozza and finally, on 11th March, he reached Madrid.
