Charles only stayed in Rome three days, utterly depressed because the pope had refused to receive him in spite of his entreaties.

And in these three days, instead of listening to Giuliano delta Rovere, who was advising him once more to call a council and depose the pope, he rather hoped to bring the pope round to his side by the virtuous act of restoring the citadels of Terracina and Civita Vecchia to the authorities of the Romagna, only keeping for himself Ostia, which he had promised Giuliano to give back to him.

At last, when the three days had elapsed, he left Rome, and resumed his march in three columns towards Tuscany, crossed the States of the Church, and on the 13th reached Siena, where he was joined by Philippe de Commines, who had gone as ambassador extraordinary to the Venetian Republic, and now announced that the enemy had forty thousand men under arms and were preparing for battle.

This news produced no other effect an the king and the gentlemen of his army than to excite their amusement beyond measure; for they had conceived such a contempt for their enemy by their easy conquest, that they could not believe that any army, however numerous, would venture to oppose their passage.
Charles, however, was forced to give way in the face of facts, when he heard at San Teranza that his vanguard, commanded by Marechal de Gie, and composed of six hundred lances and fifteen hundred Swiss, when it arrived at Fornova had come face to face with the confederates, who had encamped at Guiarole.

The marechal had ordered an instant halt, and he too had pitched his tents, utilising for his defence the natural advantages of the hilly ground.