The fight between the men of Castruccio and those of the enemy who succeeded in crossing was sharp and terrible; both sides fought with the utmost desperation and neither would yield.

The soldiers of Castruccio fought to drive the others back into the river, whilst the Florentines strove to get a footing on land in order to make room for the others pressing forward, who if they could but get out of the water would be able to fight, and in this obstinate conflict they were urged on by their captains.

Castruccio shouted to his men that these were the same enemies whom they had before conquered at Serravalle, whilst the Florentines reproached each other that the many should be overcome by the few.

At length Castruccio, seeing how long the battle had lasted, and that both his men and the enemy were utterly exhausted, and that both sides had many killed and wounded, pushed forward another body of infantry to take up a position at the rear of those who were fighting; he then commanded these latter to open their ranks as if they intended to retreat, and one part of them to turn to the right and another to the left.

This cleared a space of which the Florentines at once took advantage, and thus gained possession of a portion of the battlefield.
But when these tired soldiers found themselves at close quarters with Castruccio's reserves they could not stand against them and at once fell back into the river.