On 27 August 1268 yet another battle took place on the edge of Rome between King Charles of Anjou, rushing to the defense of the Pope, and Conradin leading a Ghibelline army: the outcome was a Guelph victory.

It seems that the trick worked, because in the early morning the Ghibellines retreated to San Marziale, and remained on the hill Poggio ai Berci.

Marshal Giambertoldo ordered the Colle militias to get around that hill and to remain hidden until the moment he appeared with the insignia of Florence in front of the Siena troops and attacked them.

Once in sight of the Ghibellines, Gianbertoldo started the battle, while Colle inhabitants were shouting and waving their weapons, giving the feeling that more troops were waiting to attack.

All this happened under the eyes of Provenzano's paternal aunt Sapia Salvani of Siena, sung by Dante's Divine Comedy (Purgatorio, Canto XIII et seq.