Gathering from these advices that it was Louis's wish that the Florentines should not be molested further, and naturally anxious not to run counter to the king's intentions, Cesare perceived that the time to take action had arrived, the time for passivity in the affairs of Florence was at an end.
So he dispatched an envoy to Vitelli, ordering his instant evacuation of Arezzo and his withdrawal with his troops from Tuscany, and he backed the command by a threat to compel Vitelli by force of arms, and to punish disobedience by depriving him of his state of Citta di Castello--"a matter," Cesare informed him, "which would be easily accomplished, as the best men of that State have already offered themselves to me." It was a command which Vitelli had no choice but to obey, not being in sufficient force to oppose the duke.

So on July 29, with Gianpaolo Baglioni, he relinquished the possession of Arezzo and departed out of Tuscany, as he had been bidden.

But so incensed was he against the duke for this intervention between himself and his revenge, and so freely did he express himself in the matter, that it was put about at once that he intended to go against Cesare.
And that is the first hint of the revolt of the condottieri.
Having launched that interdict of his, Cesare, on July 25, in the garb of a knight of St.John of Jerusalem, and with only four attendants, departed secretly from Urbino to repair to Milan and King Louis.

He paused for fresh horses at Forli on the morrow, and on the 28th reached Ferrara, where he remained for a couple of hours to visit Lucrezia, who was now in convalescence.

Ahead of him he dispatched, thence, a courier to Milan to announce his coming, and, accompanied by Alfonso d'Este, resumed his journey.
Meanwhile, the assembly of Cesare's enemies had been increasing daily in Milan, whither they repaired to support Louis and to vent their hatred of Cesare and their grievances against him.