At the service of Federico Gonzaga
In 1519, after the death of Francesco Gonzaga Marquis of Mantua (29th March) and of Lorenzo de’ Medici Duke of Urbino (4th May), Castiglione was sent to Rome for a few months by the Gonzagas, to the Papal Court, as an extraordinary ambassador, with the role of caring for the interests of the young Marquis Federico, and to obtain the reintegration of Francesco Maria Della Rovere.
In Rome, together with his friend Raffaello, he wrote a long epistle to Leone X, about safeguarding and restoring the city’s archaeological patrimony. Furthermore, he composed for his wife one of his most famous Latin poems, the Elegia qua fingit Hyppoliten suam ad se ipsum scribentem.
By means of negotiations with Leone X, Castiglione succeeded in re-establishing good diplomatic relations, putting an end to a period of growing attrition between the Gonzagas and the Pope, even if the latter refused obstinately to return the state of Urbino to the ousted Duke. With these results Baldassarre returned to Mantua in November 1519, accompanied by two short messages praising him from the Pope, addressed to the Marchioness Isabella and the Marquis Federico. It was in this context that Castiglione’s move matured, progressively and irreversibly, from one master to another: with caution and firmness he released himself from Francesco Maria Della Rovere to enter, officially and stably, into the service of Federico Gonzaga.
In these months, following the death of the Marquis Francesco Gonzaga, with the complicity and favour of the young Federico and his mother Isabella d’Este, Castiglione affirmed himself not only as the executor, but also as the inspirer of all the new political strategies undertaken by the state of Mantua. Thus, in July 1520 he was once again in Rome, where he manoeuvred diplomatically to strengthen the relationship between the State of the Church and the lords of Mantua, to secure for the Gonzagas a position of prominence, and to forge alliances useful for Italy in its defence against foreign invaders, French and Imperial.
On 12th December, he informed Federico that he had obtained for him, from the Pope, the title of captain General of the Armies of the Church: this was for Castiglione a great diplomatic success.
