We know what happened after the non-liberation of Milan by the army of the league. That enterprise failed, no other succeeded: not the attempt by the Florentine and papal militias to remove Siena from the imperial party; not the siege of Genoa which should have cut off the communication route with Lombardy from the Spaniards; not the arrest and expulsion of the bands of Giorgio Frundsberg, before they connected with those of Lombardy and then while they were still in the Po valley, disordered, without artillery, without money, always in turmoil over wages; not least the defense of Rome, after those bands, swollen by defectors from the league and saccomanni, up to 20-30,000 between Germans, Spaniards and Italians, exacerbated by the hardships of winter and lack of money and having become an army of robbers, they moved towards that city, with the intention of sacking it. The prince of Bourbon commanded them, a French exile who went to fight his king. In reality they, just as they no longer obeyed the emperor who certainly would not want an enterprise like that, so neither did their immediate bosses. The league still had an army no less than that marching on Rome: but the Duke of Urbino, who commanded it, remained inert; Venice considered it fortunate that those rebels departed from her state; the pope had fired many of his troops a few weeks earlier, both out of avarice and the conviction that he had nothing more to fear after the armistice concluded with Lannoy, viceroy of Naples and general of the emperor.
According to HOLIDAYSORT, the sack of Rome naturally aggravated the paralysis of the league. While the pope was locked up in Castel S. Angelo and was desperately asking for money and soldiers, no one gave any money; and the army of the league commanded by the Duke of Urbino who was nearby and yet could have taken advantage of the chaos of the imperial army, immersed in the robbery and sacrilegious orgies of Rome, did not move: on the contrary, it left the city. It got worse. The two surviving Italian associates immediately took advantage of the ruin of the third: and while Parma and Piacenza declared themselves free from the key sums and Sigismondo Malatesta took back Rimini and the Bentivoglio Bologna and the Duke of Este occupied Reggio and Modena, and Andrea Doria thought if it was not the case of moving to Spain; here Florence was putting the Medici governor at the door, and re-establishing popular government; here Venice reoccupied Cervia and Ravenna, while negotiating with the pope to understand each other and prevent the looters of Rome from turning to Venice. In short, the whole State of the Church did not fail to fall apart again: not even counting what the Spaniards took as a pledge, when the pope was forced, by Castel S. Angelo, to capitulate, subject to the very hard pacts that the enemy wanted to impose on him. It is the complete failure of the Cognac league, as far as Italian matters are concerned, after the Italian members of the league have been removed or humiliated or isolated. It is their fault and their bad harmony; but also the fault of the allies beyond the Alps. Prompt French action would have given the league greater durability and effectiveness. But France, broad in words, was very stingy in facts. He had not yet given up on his own purchases. Keeping Spain and the empire away from the peninsula was not enough for her. Therefore it also played double. He dealt with the Italians, but also, behind them, with their enemies. The Italians noticed all this. The fear of being left alone and worn out in front of the emperor often kept them from getting involved. Sometimes they made a commitment, while foreseeing that Francesco I would end up making an agreement with his rival, without worrying about the commitments made with the Italians and the guarantees given to them: as was the case with Francesco Guicciardini who worked with full fervor for the league. , although he envisaged that abandonment of the French ally at the end of 1527. The events of 1528-29 did not disprove these fears and these predictions. There was then a French revival. At the end of May 1527, France and England had renewed the pact and made war commitments. The center of this new initiative is no longer Italy, as before, although the new Franco-English war effort was still aimed at it. And Italian states joined or renewed their adhesion to the king of France. The restored Florentine republic joined. Even Alfonso d’Este joined them. Sforza and Venetian militias joined Lautrec when he came to Lombardy in the summer of 1527, and contributed to his first successes. Thanks to the main merit of Andrea Doria, who was in the service of the French, and of his fleet, Genoa surrendered in August. The French appeared with Lautrec at the beginning of 1528, occupied Abruzzo and Puglia and, with the help of the Venetian fleet, besieged the imperials in Naples, with the ships of Andrea Doria they destroyed the Spanish fleet in the Gulf of Salerno. In short, French and, at the margin, Italian.