The Florentines, having occupied San Miniato, held a council of war to
decide whether they should attack Pisa or the army of Castruccio, and,
having weighed the difficulties of both courses, they decided upon the
latter. The river Arno was at that time low enough to be fordable, yet
the water reached to the shoulders of the infantrymen and to the
saddles of the horsemen. On the morning of 10 June 1328, the
Florentines commenced the battle by ordering forward a number of
cavalry and ten thousand infantry. Castruccio, whose plan of action was
fixed, and who well knew what to do, at once attacked the Florentines
with five thousand infantry and three thousand horsemen, not allowing
them to issue from the river before he charged them; he also sent one
thousand light infantry up the river bank, and the same number down the
Arno. The infantry of the Florentines were so much impeded by their
arms and the water that they were not able to mount the banks of the
river, whilst the cavalry had made the passage of the river more
difficult for the others, by reason of the few who had crossed having
broken up the bed of the river, and this being deep with mud, many of
the horses rolled over with their riders and many of them had stuck so
fast that they could not move. When the Florentine captains saw the
difficulties their men were meeting, they withdrew them and moved
higher up the river, hoping to find the river bed less treacherous and
the banks more adapted for landing. These men were met at the bank by
the forces which Castruccio had already sent forward, who, being light
armed with bucklers and javelins in their hands, let fly with
tremendous shouts into the faces and bodies of the cavalry. The horses,
alarmed by the noise and the wounds, would not move forward, and
trampled each other in great confusion. 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