Roberto Malatesta was serving under the Duke of Calabria at the surrender of Monte Sansovino, and, having quarrelled with him for sanctioning a sack of that place, he, with a condottiere's easy conscience, transferred his company to the Florentine camp. There, too, were assembled the Duke of Ferrara, the Marquis of Mantua, Costanzo Sforza of Pesaro, Nicolò Vitelli of Città di Castello, Carlo Braccio of Montone. The promise afforded by these names proved, however, illusory; and although a diversion was made by them in June towards Perugia, the spring and summer again passed without notable efforts on either side. This number of independent leaders, serving under no recognised head, embarrassed the allies; and although they obtained some inconsiderable successes near Thrasymene, the other division of their forces sustained a decided check at Poggio Imperiale, in Val d'Elsa, on the 7th of September. The ecclesiastical forces, following up their advantage, laid siege to Certaldo and Poggibonsi, both of which speedily fell. They next attacked Colle, which held out till the 12th of November; its surrender, and the approach of winter, led to a three months' truce, and the troops repaired to quarters. Comines, then resident at Florence as envoy from the French Court, criticises these operations as inert, and considers the Italians as inferior to his countrymen in the attack or defence of fortified places, but admits their superiority in the quartermaster's department, and in commissariat arrangements.