In truth, the Duke's own affairs required his full attention, for the power of the Medici, though shaken, was still formidable, and its natural representative, the Cardinal Giulio, was influential in the Sacred College, and almost sovereign at Florence. Francesco Maria therefore observed a prudent neutrality, when the Bande Nere advanced to support the claims of Gentile Baglioni upon Perugia. These, being warned off the ecclesiastical territory by the consistory, turned up the valley of the Tiber, and, passing the Apennines, made a descent upon Montefeltro, where they plundered until the end of February,--an outrage for which the Cardinal was greatly blamed, as a convention had already been signed between him and the Duke for their respective states of Florence and Urbino. Much light is thrown upon these very complicated transactions by a careful examination of Castiglione's letters. To his dexterous diplomacy that convention seems to have been chiefly owing. He endeavoured to clench the reconciliation by an engagement for Francesco Maria in the Florentine service, and a marriage between Prince Guidobaldo of Urbino and Caterina de' Medici, daughter of Lorenzo, and heiress of his pretensions. The failure of this plan, from backwardness on the part of the Cardinal rather than of the Duke, was, perhaps, fortunate for the intended bridegroom's domestic peace; and the contending claims which it was meant to solve never ripened into importance. The condotta had a better issue: avowedly for but one year, it seems to have been intended rather to neutralise a troublesome foe than with the idea of calling the Duke's service into actual requisition. Indeed, although he was nominally captain-general, with 9000 ducats of pay, besides 100 broad scudi for each of his two hundred men-at-arms in white uniform (three mounted soldiers counting as one man-at-arms), this was expressly their peace establishment and pay, to be increased in case of war.[288] Castiglione's success in these arrangements was facilitated by his having confided to Cardinal Giulio a refusal at this time, by Francesco Maria, of very flattering proposals from the French court, and the same good offices extended to disabusing the Duke in the eyes of Emanuel, the imperial ambassador, who, believing him committed to Francis, was countermining his interests in the consistory, and with the Cardinal. [Footnote 288: Archivio Diplomatico of Florence, May 25, 1522.]