The great captains under or from whom Federigo had gathered his laurels were now all dead, and his military reputation far transcended that of any remaining condottiere. It was, therefore, not without jealousy that the powers of Upper Italy saw him establish relations of such close amity with the Pope and Ferdinand. Other matters tended to aggravate the feelings of alarm thus generated. Not satisfied with indulging his nepotism at the expense of the Holy See, Sixtus showed tendencies to an aggressive policy against his neighbours. A portion of the treasure supposed to have been accumulated by his avaricious predecessor, but of which he gave no account, was suspected to have been employed in purchasing for his favourite nephew, Girolamo, the seigneury of Imola from the Manfredi. A local squabble at Todi, dignified with the almost forgotten watchwords of Guelph and Ghibelline, afforded him a pretext for sending thither another nephew, the Cardinal della Rovere, at the head of an army, which, though marching under the papal banner, sided with the self-styled imperialist faction. The Pontiff, who had long seen with regret the feeble hold which his predecessors maintained over their vassals, and even over the nominal subjects of the Church, commissioned his legate to carry out the good work thus begun. Accordingly, after chastising Todi and Spoleto, Giuliano advanced into the upper valley of the Tiber, in order to reduce Città di Castello, where the Vitelli had for some time exercised absolute sovereignty with the title of Vicar. To this expedition the Duke of Urbino gave his aid, and on its successful issue carried several of that family to Rome, in order to intercede for their pardon. These events accelerated arrangements in the north for a combination calculated to balance the threatening attitude of the southern powers, and in November a defensive treaty was signed by Milan, Venice, and Florence, under reservation, however, to the Pope and King of Naples to accede to the new league. Of this they declined availing themselves, content with general professions of moderation and peace, which, fortunately acted upon, prolonged the general tranquillity of Italy, and enabled her energies to be directed with tolerable unanimity against the Turks. The three years of renewed repose which followed were spent by Federigo at home, in the indulgence of those humane tastes which signalised his court, and laid a foundation for that cultivation of mind by which Urbino became distinguished. This may accordingly be the best place to review his patronage of letters.