Shortly after this the Florentines were relieved in some degree of the pressure of Castruccio’s army, owing to his being compelled to leave his positions before Florence and march on Pisa, in order to suppress a conspiracy that had been raised against him by Benedetto Lanfranchi, one of the first men in Pisa, who could not endure that his fatherland should be under the dominion of the Lucchese. He had formed this conspiracy, intending to seize the citadel, kill the partisans of Castruccio, and drive out the garrison. As, however, in a conspiracy paucity of numbers is essential to secrecy, so for its execution a few are not sufficient, and in seeking more adherents to his conspiracy Lanfranchi encountered a person who revealed the design to Castruccio. This betrayal cannot be passed by without severe reproach to Bonifacio Cerchi and Giovanni Guidi, two Florentine exiles who were suffering their banishment in Pisa. Thereupon Castruccio seized Benedetto and put him to death, and beheaded many other noble citizens, and drove their families into exile. It now appeared to Castruccio that both Pisa and Pistoia were thoroughly disaffected; he employed much thought and energy upon securing his position there, and this gave the Florentines their opportunity to reorganize their army, and to await the coming of Carlo, the son of the King of Naples. When Carlo arrived they decided to lose no more time, and assembled a great army of more than thirty thousand infantry and ten thousand cavalry—having called to their aid every Guelph there was in Italy. They consulted whether they should attack Pistoia or Pisa first, and decided that it would be better to march on the latter—a course, owing to the recent conspiracy, more likely to succeed, and of more advantage to them, because they believed that the surrender of Pistoia would follow the acquisition of Pisa.
In the early part of May 1328, the Florentines put in motion this army and quickly occupied Lastra, Signa, Montelupo, and Empoli, passing from thence on to San Miniato. When Castruccio heard of the enormous army which the Florentines were sending against him, he was in no degree alarmed, believing that the time had now arrived when Fortune would deliver the empire of Tuscany into his hands, for he had no reason to think that his enemy would make a better fight, or had better prospects of success, than at Pisa or Serravalle. He assembled twenty thousand foot soldiers and four thousand horsemen, and with this army went to Fucecchio, whilst he sent Pagolo Guinigi to Pisa with five thousand infantry. Fucecchio has a stronger position than any other town in the Pisan district, owing to its situation between the rivers Arno and Gusciana and its slight elevation above the surrounding plain. Moreover, the enemy could not hinder its being victualled unless they divided their forces, nor could they approach it either from the direction of Lucca or Pisa, nor could they get through to Pisa, or attack Castruccio’s forces except at a disadvantage. In one case they would find themselves placed between his two armies, the one under his own command and the other under Pagolo, and in the other case they would have to cross the Arno to get to close quarters with the enemy, an undertaking of great hazard. In order to tempt the Florentines to take this latter course, Castruccio withdrew his men from the banks of the river and placed them under the walls of Fucecchio, leaving a wide expanse of land between them and the river.
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 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. The cavalry of either side had not as yet gained any decisive advantage over the other, because Castruccio, knowing his inferiority in this arm, had commanded his leaders only to stand on the defensive against the attacks of their adversaries, as he hoped that when he had overcome the infantry he would be able to make short work of the cavalry. This fell out as he had hoped, for when he saw the Florentine army driven back across the river he ordered the remainder of his infantry to attack the cavalry of the enemy. This they did with lance and javelin, and, joined by their own cavalry, fell upon the enemy with the greatest fury and soon put him to flight. The Florentine captains, having seen the difficulty their cavalry had met with in crossing the river, had attempted to make their infantry cross lower down the river, in order to attack the flanks of Castruccio’s army. But here, also, the banks were steep and already lined by the men of Castruccio, and this movement was quite useless. Thus the Florentines were so completely defeated at all points that scarcely a third of them escaped, and Castruccio was again covered with glory. Many captains were taken prisoners, and Carlo, the son of King Ruberto, with Michelagnolo Falconi and Taddeo degli Albizzi, the Florentine commissioners, fled to Empoli. If the spoils were great, the slaughter was infinitely greater, as might be expected in such a battle. Of the Florentines there fell twenty thousand two hundred and thirty-one men, whilst Castruccio lost one thousand five hundred and seventy men.#ENGLISH